feat(daemon): Add UPSD (NUT) protocol support, Proxmox VM shutdown action, pause/resume monitoring, and network-loss/unreachable handling; bump config version to 4.2

changelog.md

@@ -1,5 +1,17 @@
 # Changelog
 
+## 2026-02-20 - 5.3.0 - feat(daemon)
+Add UPSD (NUT) protocol support, Proxmox VM shutdown action, pause/resume monitoring, and network-loss/unreachable handling; bump config version to 4.2
+
+- Add UPSD client (ts/upsd) and ProtocolResolver (ts/protocol) to support protocol-agnostic UPS queries (snmp or upsd).
+- Introduce new TProtocol and IUpsdConfig types, wire up Nupst to initialize & expose UPSD client, and route status requests through ProtocolResolver.
+- Add 'unreachable' TPowerStatus plus consecutiveFailures and unreachableSince tracking; mark UPS as unreachable after NETWORK.CONSECUTIVE_FAILURE_THRESHOLD failures and suppress shutdown actions while unreachable.
+- Implement pause/resume feature: PAUSE.FILE_PATH state file, CLI commands (pause/resume), daemon pause-state polling, auto-resume, and include pause state in HTTP API responses.
+- Add ProxmoxAction (ts/actions/proxmox-action.ts) with Proxmox API interaction, configuration options (token, node, timeout, force, insecure) and CLI prompts to configure proxmox actions.
+- CLI and UI updates: protocol selection when adding UPS, protocol/host shown in lists, action details column supports proxmox, and status displays include protocol and unreachable state.
+- Add migration MigrationV4_1ToV4_2 to set protocol:'snmp' for existing devices and bump config.version to '4.2'.
+- Add new constants (NETWORK, UPSD, PAUSE, PROXMOX), update package.json scripts (test/build/lint/format), and wire protocol support across daemon, systemd, http-server, and various handlers. 
+
 ## 2026-01-29 - 5.2.4 - fix()
 no changes
 

package.json

@@ -34,8 +34,10 @@
   "scripts": {
     "postinstall": "node scripts/install-binary.js",
     "prepublishOnly": "echo 'Publishing NUPST binaries to npm...'",
-    "test": "echo 'Tests are run with Deno: deno task test'",
+    "test": "deno task test",
-    "build": "echo 'no build needed'"
+    "build": "deno task check",
+    "lint": "deno task lint",
+    "format": "deno task fmt"
   },
   "files": [
     "bin/",

readme.hints.md

@@ -12,8 +12,9 @@
 
 2. **Constants File (`ts/constants.ts`)**
    - Centralized all magic numbers (timeouts, intervals, thresholds)
-   - Contains: `TIMING`, `SNMP`, `THRESHOLDS`, `WEBHOOK`, `SCRIPT`, `SHUTDOWN`, `HTTP_SERVER`, `UI`
+   - Contains: `TIMING`, `SNMP`, `THRESHOLDS`, `WEBHOOK`, `SCRIPT`, `SHUTDOWN`, `HTTP_SERVER`, `UI`,
-   - Used in: `daemon.ts`, `snmp/manager.ts`, `actions/*.ts`
+     `NETWORK`, `UPSD`, `PAUSE`, `PROXMOX`
+   - Used in: `daemon.ts`, `snmp/manager.ts`, `actions/*.ts`, `upsd/client.ts`
 
 3. **Logger Consistency**
    - Replaced all `console.log/console.error` in `snmp/manager.ts` with proper `logger.*` calls
@@ -35,13 +36,47 @@
    - Uses: `IUpsConfig`, `INupstConfig`, `ISnmpConfig`, `IActionConfig`, `IThresholds`,
      `ISnmpUpsStatus`
 
+## Features Added (February 2026)
+
+### Network Loss Handling
+- `TPowerStatus` extended with `'unreachable'` state
+- `IUpsStatus` has `consecutiveFailures` and `unreachableSince` tracking
+- After `NETWORK.CONSECUTIVE_FAILURE_THRESHOLD` (3) failures, UPS transitions to `unreachable`
+- Shutdown action explicitly won't fire on `unreachable` (prevents false shutdowns)
+- Recovery is logged when UPS comes back from unreachable
+
+### UPSD/NIS Protocol Support
+- New `ts/upsd/` directory with TCP client for NUT (Network UPS Tools) servers
+- `ts/protocol/` directory with `ProtocolResolver` for protocol-agnostic status queries
+- `IUpsConfig.protocol` field: `'snmp'` (default) or `'upsd'`
+- `IUpsConfig.snmp` is now optional (not needed for UPSD devices)
+- CLI supports protocol selection during `nupst ups add`
+- Config version bumped to `4.2` with migration from `4.1`
+
+### Pause/Resume Command
+- File-based signaling via `/etc/nupst/pause` JSON file
+- `nupst pause [--duration 30m|2h|1d]` creates pause file
+- `nupst resume` deletes pause file
+- Daemon polls continue but actions are suppressed while paused
+- Auto-resume after duration expires
+- HTTP API includes pause state in response
+
+### Proxmox VM Shutdown Action
+- New action type `'proxmox'` in `ts/actions/proxmox-action.ts`
+- Uses Proxmox REST API with PVEAPIToken authentication
+- Shuts down QEMU VMs and LXC containers before host shutdown
+- Supports: exclude IDs, configurable timeout, force-stop, TLS skip for self-signed certs
+- Should be placed BEFORE shutdown actions in the action chain
+
 ## Architecture Notes
 
 - **SNMP Manager**: Uses `INupstAccessor` interface (not direct `Nupst` reference) to avoid circular
   imports
+- **Protocol Resolver**: Routes to SNMP or UPSD based on `IUpsConfig.protocol`
 - **CLI Handlers**: All use the `helpers.withPrompt()` utility for interactive input
 - **Constants**: All timing values should be referenced from `ts/constants.ts`
 - **Actions**: Use `IActionConfig` from `ts/actions/base-action.ts` for action configuration
+- **Config version**: Currently `4.2`, migrations run automatically
 
 ## File Organization
 
@@ -54,9 +89,21 @@ ts/
 │   ├── prompt.ts         # Readline utility
 │   └── shortid.ts        # ID generation
 ├── actions/
-│   ├── base-action.ts    # Base action class and interfaces
+│   ├── base-action.ts    # Base action class, IActionConfig, TPowerStatus
 │   ├── webhook-action.ts # Includes IWebhookPayload
+│   ├── proxmox-action.ts # Proxmox VM/LXC shutdown
 │   └── ...
+├── upsd/
+│   ├── types.ts          # IUpsdConfig
+│   ├── client.ts         # NupstUpsd TCP client
+│   └── index.ts
+├── protocol/
+│   ├── types.ts          # TProtocol = 'snmp' | 'upsd'
+│   ├── resolver.ts       # ProtocolResolver
+│   └── index.ts
+├── migrations/
+│   ├── migration-runner.ts
+│   └── migration-v4.1-to-v4.2.ts  # Adds protocol field
 └── cli/
     └── ...               # All handlers use helpers.withPrompt()
 ```

ts/00_commitinfo_data.ts

@@ -3,6 +3,6 @@
  */
 export const commitinfo = {
   name: '@serve.zone/nupst',
-  version: '5.2.4',
+  version: '5.3.0',
   description: 'Network UPS Shutdown Tool - Monitor SNMP-enabled UPS devices and orchestrate graceful system shutdowns during power emergencies'
 }

ts/actions/base-action.ts

@@ -6,7 +6,7 @@
  * 2. Threshold violations (battery/runtime cross below configured thresholds)
  */
 
-export type TPowerStatus = 'online' | 'onBattery' | 'unknown';
+export type TPowerStatus = 'online' | 'onBattery' | 'unknown' | 'unreachable';
 
 /**
  * Context provided to actions when they execute
@@ -52,7 +52,7 @@ export type TActionTriggerMode =
  */
 export interface IActionConfig {
   /** Type of action to execute */
-  type: 'shutdown' | 'webhook' | 'script';
+  type: 'shutdown' | 'webhook' | 'script' | 'proxmox';
 
   // Trigger configuration
   /**
@@ -96,6 +96,26 @@ export interface IActionConfig {
   scriptTimeout?: number;
   /** Only execute script on threshold violation */
   scriptOnlyOnThresholdViolation?: boolean;
+
+  // Proxmox action configuration
+  /** Proxmox API host (default: localhost) */
+  proxmoxHost?: string;
+  /** Proxmox API port (default: 8006) */
+  proxmoxPort?: number;
+  /** Proxmox node name (default: auto-detect via hostname) */
+  proxmoxNode?: string;
+  /** Proxmox API token ID (e.g., 'root@pam!nupst') */
+  proxmoxTokenId?: string;
+  /** Proxmox API token secret */
+  proxmoxTokenSecret?: string;
+  /** VM/CT IDs to exclude from shutdown */
+  proxmoxExcludeIds?: number[];
+  /** Timeout for VM/CT shutdown in seconds (default: 120) */
+  proxmoxStopTimeout?: number;
+  /** Force-stop VMs that don't shut down gracefully (default: true) */
+  proxmoxForceStop?: boolean;
+  /** Skip TLS verification for self-signed certificates (default: true) */
+  proxmoxInsecure?: boolean;
 }
 
 /**

ts/actions/index.ts

@@ -10,6 +10,7 @@ import type { Action, IActionConfig, IActionContext } from './base-action.ts';
 import { ShutdownAction } from './shutdown-action.ts';
 import { WebhookAction } from './webhook-action.ts';
 import { ScriptAction } from './script-action.ts';
+import { ProxmoxAction } from './proxmox-action.ts';
 
 // Re-export types for convenience
 export type { IActionConfig, IActionContext, TPowerStatus } from './base-action.ts';
@@ -18,6 +19,7 @@ export { Action } from './base-action.ts';
 export { ShutdownAction } from './shutdown-action.ts';
 export { WebhookAction } from './webhook-action.ts';
 export { ScriptAction } from './script-action.ts';
+export { ProxmoxAction } from './proxmox-action.ts';
 
 /**
  * ActionManager - Coordinates action creation and execution
@@ -40,6 +42,8 @@ export class ActionManager {
         return new WebhookAction(config);
       case 'script':
         return new ScriptAction(config);
+      case 'proxmox':
+        return new ProxmoxAction(config);
       default:
         throw new Error(`Unknown action type: ${(config as IActionConfig).type}`);
     }

ts/actions/proxmox-action.ts

@@ -0,0 +1,352 @@
+import * as os from 'node:os';
+import { Action, type IActionContext } from './base-action.ts';
+import { logger } from '../logger.ts';
+import { PROXMOX, UI } from '../constants.ts';
+
+/**
+ * ProxmoxAction - Gracefully shuts down Proxmox VMs and LXC containers
+ *
+ * Uses the Proxmox REST API via HTTPS with API token authentication.
+ * Shuts down running QEMU VMs and LXC containers, waits for completion,
+ * and optionally force-stops any that don't respond.
+ *
+ * This action should be placed BEFORE shutdown actions in the action chain
+ * so that VMs are stopped before the host is shut down.
+ */
+export class ProxmoxAction extends Action {
+  readonly type = 'proxmox';
+
+  /**
+   * Execute the Proxmox shutdown action
+   */
+  async execute(context: IActionContext): Promise<void> {
+    if (!this.shouldExecute(context)) {
+      logger.info(
+        `Proxmox action skipped (trigger mode: ${
+          this.config.triggerMode || 'powerChangesAndThresholds'
+        })`,
+      );
+      return;
+    }
+
+    const host = this.config.proxmoxHost || PROXMOX.DEFAULT_HOST;
+    const port = this.config.proxmoxPort || PROXMOX.DEFAULT_PORT;
+    const node = this.config.proxmoxNode || os.hostname();
+    const tokenId = this.config.proxmoxTokenId;
+    const tokenSecret = this.config.proxmoxTokenSecret;
+    const excludeIds = new Set(this.config.proxmoxExcludeIds || []);
+    const stopTimeout = (this.config.proxmoxStopTimeout || PROXMOX.DEFAULT_STOP_TIMEOUT_SECONDS) * 1000;
+    const forceStop = this.config.proxmoxForceStop !== false; // default true
+    const insecure = this.config.proxmoxInsecure !== false; // default true
+
+    if (!tokenId || !tokenSecret) {
+      logger.error('Proxmox API token ID and secret are required');
+      return;
+    }
+
+    const baseUrl = `https://${host}:${port}${PROXMOX.API_BASE}`;
+    const headers: Record<string, string> = {
+      'Authorization': `PVEAPIToken=${tokenId}=${tokenSecret}`,
+    };
+
+    logger.log('');
+    logger.logBoxTitle('Proxmox VM Shutdown', UI.WIDE_BOX_WIDTH, 'warning');
+    logger.logBoxLine(`Node: ${node}`);
+    logger.logBoxLine(`API: ${host}:${port}`);
+    logger.logBoxLine(`UPS: ${context.upsName} (${context.powerStatus})`);
+    logger.logBoxLine(`Trigger: ${context.triggerReason}`);
+    if (excludeIds.size > 0) {
+      logger.logBoxLine(`Excluded IDs: ${[...excludeIds].join(', ')}`);
+    }
+    logger.logBoxEnd();
+    logger.log('');
+
+    try {
+      // Collect running VMs and CTs
+      const runningVMs = await this.getRunningVMs(baseUrl, node, headers, insecure);
+      const runningCTs = await this.getRunningCTs(baseUrl, node, headers, insecure);
+
+      // Filter out excluded IDs
+      const vmsToStop = runningVMs.filter((vm) => !excludeIds.has(vm.vmid));
+      const ctsToStop = runningCTs.filter((ct) => !excludeIds.has(ct.vmid));
+
+      const totalToStop = vmsToStop.length + ctsToStop.length;
+      if (totalToStop === 0) {
+        logger.info('No running VMs or containers to shut down');
+        return;
+      }
+
+      logger.info(`Shutting down ${vmsToStop.length} VMs and ${ctsToStop.length} containers...`);
+
+      // Send shutdown commands to all VMs and CTs
+      for (const vm of vmsToStop) {
+        await this.shutdownVM(baseUrl, node, vm.vmid, headers, insecure);
+        logger.dim(`  Shutdown sent to VM ${vm.vmid} (${vm.name || 'unnamed'})`);
+      }
+
+      for (const ct of ctsToStop) {
+        await this.shutdownCT(baseUrl, node, ct.vmid, headers, insecure);
+        logger.dim(`  Shutdown sent to CT ${ct.vmid} (${ct.name || 'unnamed'})`);
+      }
+
+      // Poll until all stopped or timeout
+      const allIds = [
+        ...vmsToStop.map((vm) => ({ type: 'qemu' as const, vmid: vm.vmid, name: vm.name })),
+        ...ctsToStop.map((ct) => ({ type: 'lxc' as const, vmid: ct.vmid, name: ct.name })),
+      ];
+
+      const remaining = await this.waitForShutdown(
+        baseUrl,
+        node,
+        allIds,
+        headers,
+        insecure,
+        stopTimeout,
+      );
+
+      if (remaining.length > 0 && forceStop) {
+        logger.warn(`${remaining.length} VMs/CTs didn't shut down gracefully, force-stopping...`);
+        for (const item of remaining) {
+          try {
+            if (item.type === 'qemu') {
+              await this.stopVM(baseUrl, node, item.vmid, headers, insecure);
+            } else {
+              await this.stopCT(baseUrl, node, item.vmid, headers, insecure);
+            }
+            logger.dim(`  Force-stopped ${item.type} ${item.vmid} (${item.name || 'unnamed'})`);
+          } catch (error) {
+            logger.error(
+              `  Failed to force-stop ${item.type} ${item.vmid}: ${
+                error instanceof Error ? error.message : String(error)
+              }`,
+            );
+          }
+        }
+      } else if (remaining.length > 0) {
+        logger.warn(`${remaining.length} VMs/CTs still running (force-stop disabled)`);
+      }
+
+      logger.success('Proxmox shutdown sequence completed');
+    } catch (error) {
+      logger.error(
+        `Proxmox action failed: ${error instanceof Error ? error.message : String(error)}`,
+      );
+    }
+  }
+
+  /**
+   * Make an API request to the Proxmox server
+   */
+  private async apiRequest(
+    url: string,
+    method: string,
+    headers: Record<string, string>,
+    insecure: boolean,
+  ): Promise<unknown> {
+    const fetchOptions: RequestInit = {
+      method,
+      headers,
+    };
+
+    // Use NODE_TLS_REJECT_UNAUTHORIZED for insecure mode (self-signed certs)
+    if (insecure) {
+      // deno-lint-ignore no-explicit-any
+      (globalThis as any).process?.env && ((globalThis as any).process.env.NODE_TLS_REJECT_UNAUTHORIZED = '0');
+    }
+
+    try {
+      const response = await fetch(url, fetchOptions);
+
+      if (!response.ok) {
+        const body = await response.text();
+        throw new Error(`Proxmox API error ${response.status}: ${body}`);
+      }
+
+      return await response.json();
+    } finally {
+      // Restore TLS verification
+      if (insecure) {
+        // deno-lint-ignore no-explicit-any
+        (globalThis as any).process?.env && ((globalThis as any).process.env.NODE_TLS_REJECT_UNAUTHORIZED = '1');
+      }
+    }
+  }
+
+  /**
+   * Get list of running QEMU VMs
+   */
+  private async getRunningVMs(
+    baseUrl: string,
+    node: string,
+    headers: Record<string, string>,
+    insecure: boolean,
+  ): Promise<Array<{ vmid: number; name: string }>> {
+    try {
+      const response = await this.apiRequest(
+        `${baseUrl}/nodes/${node}/qemu`,
+        'GET',
+        headers,
+        insecure,
+      ) as { data: Array<{ vmid: number; name: string; status: string }> };
+
+      return (response.data || [])
+        .filter((vm) => vm.status === 'running')
+        .map((vm) => ({ vmid: vm.vmid, name: vm.name || '' }));
+    } catch (error) {
+      logger.error(
+        `Failed to list VMs: ${error instanceof Error ? error.message : String(error)}`,
+      );
+      return [];
+    }
+  }
+
+  /**
+   * Get list of running LXC containers
+   */
+  private async getRunningCTs(
+    baseUrl: string,
+    node: string,
+    headers: Record<string, string>,
+    insecure: boolean,
+  ): Promise<Array<{ vmid: number; name: string }>> {
+    try {
+      const response = await this.apiRequest(
+        `${baseUrl}/nodes/${node}/lxc`,
+        'GET',
+        headers,
+        insecure,
+      ) as { data: Array<{ vmid: number; name: string; status: string }> };
+
+      return (response.data || [])
+        .filter((ct) => ct.status === 'running')
+        .map((ct) => ({ vmid: ct.vmid, name: ct.name || '' }));
+    } catch (error) {
+      logger.error(
+        `Failed to list CTs: ${error instanceof Error ? error.message : String(error)}`,
+      );
+      return [];
+    }
+  }
+
+  /**
+   * Send graceful shutdown to a QEMU VM
+   */
+  private async shutdownVM(
+    baseUrl: string,
+    node: string,
+    vmid: number,
+    headers: Record<string, string>,
+    insecure: boolean,
+  ): Promise<void> {
+    await this.apiRequest(
+      `${baseUrl}/nodes/${node}/qemu/${vmid}/status/shutdown`,
+      'POST',
+      headers,
+      insecure,
+    );
+  }
+
+  /**
+   * Send graceful shutdown to an LXC container
+   */
+  private async shutdownCT(
+    baseUrl: string,
+    node: string,
+    vmid: number,
+    headers: Record<string, string>,
+    insecure: boolean,
+  ): Promise<void> {
+    await this.apiRequest(
+      `${baseUrl}/nodes/${node}/lxc/${vmid}/status/shutdown`,
+      'POST',
+      headers,
+      insecure,
+    );
+  }
+
+  /**
+   * Force-stop a QEMU VM
+   */
+  private async stopVM(
+    baseUrl: string,
+    node: string,
+    vmid: number,
+    headers: Record<string, string>,
+    insecure: boolean,
+  ): Promise<void> {
+    await this.apiRequest(
+      `${baseUrl}/nodes/${node}/qemu/${vmid}/status/stop`,
+      'POST',
+      headers,
+      insecure,
+    );
+  }
+
+  /**
+   * Force-stop an LXC container
+   */
+  private async stopCT(
+    baseUrl: string,
+    node: string,
+    vmid: number,
+    headers: Record<string, string>,
+    insecure: boolean,
+  ): Promise<void> {
+    await this.apiRequest(
+      `${baseUrl}/nodes/${node}/lxc/${vmid}/status/stop`,
+      'POST',
+      headers,
+      insecure,
+    );
+  }
+
+  /**
+   * Wait for VMs/CTs to shut down, return any that are still running after timeout
+   */
+  private async waitForShutdown(
+    baseUrl: string,
+    node: string,
+    items: Array<{ type: 'qemu' | 'lxc'; vmid: number; name: string }>,
+    headers: Record<string, string>,
+    insecure: boolean,
+    timeout: number,
+  ): Promise<Array<{ type: 'qemu' | 'lxc'; vmid: number; name: string }>> {
+    const startTime = Date.now();
+    let remaining = [...items];
+
+    while (remaining.length > 0 && (Date.now() - startTime) < timeout) {
+      // Wait before polling
+      await new Promise((resolve) => setTimeout(resolve, PROXMOX.STATUS_POLL_INTERVAL_SECONDS * 1000));
+
+      // Check which are still running
+      const stillRunning: typeof remaining = [];
+
+      for (const item of remaining) {
+        try {
+          const statusUrl = `${baseUrl}/nodes/${node}/${item.type}/${item.vmid}/status/current`;
+          const response = await this.apiRequest(statusUrl, 'GET', headers, insecure) as {
+            data: { status: string };
+          };
+
+          if (response.data?.status === 'running') {
+            stillRunning.push(item);
+          } else {
+            logger.dim(`  ${item.type} ${item.vmid} (${item.name}) stopped`);
+          }
+        } catch (_error) {
+          // If we can't check status, assume it might still be running
+          stillRunning.push(item);
+        }
+      }
+
+      remaining = stillRunning;
+
+      if (remaining.length > 0) {
+        const elapsed = Math.round((Date.now() - startTime) / 1000);
+        logger.dim(`  Waiting... ${remaining.length} still running (${elapsed}s elapsed)`);
+      }
+    }
+
+    return remaining;
+  }
+}

ts/actions/shutdown-action.ts

@@ -34,10 +34,17 @@ export class ShutdownAction extends Action {
 
     // CRITICAL SAFETY CHECK: Shutdown should NEVER trigger unless UPS is on battery
     // A low battery while on grid power is not an emergency (the battery is charging)
+    // When UPS is unreachable, we don't know the actual state - don't trigger false shutdown
     if (context.powerStatus !== 'onBattery') {
-      logger.info(
+      if (context.powerStatus === 'unreachable') {
-        `Shutdown action skipped: UPS is not on battery (status: ${context.powerStatus})`,
+        logger.info(
-      );
+          `Shutdown action skipped: UPS is unreachable (communication failure, actual state unknown)`,
+        );
+      } else {
+        logger.info(
+          `Shutdown action skipped: UPS is not on battery (status: ${context.powerStatus})`,
+        );
+      }
       return false;
     }
 

ts/actions/webhook-action.ts

@@ -14,7 +14,7 @@ export interface IWebhookPayload {
   /** UPS name */
   upsName: string;
   /** Current power status */
-  powerStatus: 'online' | 'onBattery' | 'unknown';
+  powerStatus: 'online' | 'onBattery' | 'unknown' | 'unreachable';
   /** Current battery capacity percentage */
   batteryCapacity: number;
   /** Current battery runtime in minutes */

ts/cli.ts

@@ -26,8 +26,9 @@ export class NupstCli {
     const debugOptions = this.extractDebugOptions(args);
     if (debugOptions.debugMode) {
       logger.log('Debug mode enabled');
-      // Enable debug mode in the SNMP client
+      // Enable debug mode in both protocol clients
       this.nupst.getSnmp().enableDebug();
+      this.nupst.getUpsd().enableDebug();
     }
 
     // Check for version flag
@@ -259,6 +260,12 @@ export class NupstCli {
 
     // Handle top-level commands
     switch (command) {
+      case 'pause':
+        await serviceHandler.pause(commandArgs);
+        break;
+      case 'resume':
+        await serviceHandler.resume();
+        break;
       case 'update':
         await serviceHandler.update();
         break;
@@ -351,18 +358,32 @@ export class NupstCli {
 
         // UPS Devices Table
         if (config.upsDevices.length > 0) {
-          const upsRows = config.upsDevices.map((ups) => ({
+          const upsRows = config.upsDevices.map((ups) => {
-            name: ups.name,
+            const protocol = ups.protocol || 'snmp';
-            id: theme.dim(ups.id),
+            let host = 'N/A';
-            host: `${ups.snmp.host}:${ups.snmp.port}`,
+            let model = '';
-            model: ups.snmp.upsModel || 'cyberpower',
+            if (protocol === 'upsd' && ups.upsd) {
-            actions: `${(ups.actions || []).length} configured`,
+              host = `${ups.upsd.host}:${ups.upsd.port}`;
-            groups: ups.groups.length > 0 ? ups.groups.join(', ') : theme.dim('None'),
+              model = `NUT:${ups.upsd.upsName}`;
-          }));
+            } else if (ups.snmp) {
+              host = `${ups.snmp.host}:${ups.snmp.port}`;
+              model = ups.snmp.upsModel || 'cyberpower';
+            }
+            return {
+              name: ups.name,
+              id: theme.dim(ups.id),
+              protocol: protocol.toUpperCase(),
+              host,
+              model,
+              actions: `${(ups.actions || []).length} configured`,
+              groups: ups.groups.length > 0 ? ups.groups.join(', ') : theme.dim('None'),
+            };
+          });
 
           const upsColumns: ITableColumn[] = [
             { header: 'Name', key: 'name', align: 'left', color: theme.highlight },
             { header: 'ID', key: 'id', align: 'left' },
+            { header: 'Protocol', key: 'protocol', align: 'left' },
             { header: 'Host:Port', key: 'host', align: 'left', color: theme.info },
             { header: 'Model', key: 'model', align: 'left' },
             { header: 'Actions', key: 'actions', align: 'left' },
@@ -534,6 +555,8 @@ export class NupstCli {
     this.printCommand('action <subcommand>', 'Manage UPS actions');
     this.printCommand('feature <subcommand>', 'Manage optional features');
     this.printCommand('config [show]', 'Display current configuration');
+    this.printCommand('pause [--duration <time>]', 'Pause action monitoring');
+    this.printCommand('resume', 'Resume action monitoring');
     this.printCommand('update', 'Update NUPST from repository', theme.dim('(requires root)'));
     this.printCommand('uninstall', 'Completely remove NUPST', theme.dim('(requires root)'));
     this.printCommand('help, --help, -h', 'Show this help message');

ts/cli/action-handler.ts

@@ -346,17 +346,30 @@ export class ActionHandler {
       { header: 'Battery', key: 'battery', align: 'right' },
       { header: 'Runtime', key: 'runtime', align: 'right' },
       { header: 'Trigger Mode', key: 'triggerMode', align: 'left' },
-      { header: 'Delay', key: 'delay', align: 'right' },
+      { header: 'Details', key: 'details', align: 'left' },
     ];
 
-    const rows = target.actions.map((action, index) => ({
+    const rows = target.actions.map((action, index) => {
-      index: theme.dim(index.toString()),
+      let details = `${action.shutdownDelay || 5}s delay`;
-      type: theme.highlight(action.type),
+      if (action.type === 'proxmox') {
-      battery: action.thresholds ? `${action.thresholds.battery}%` : theme.dim('N/A'),
+        const host = action.proxmoxHost || 'localhost';
-      runtime: action.thresholds ? `${action.thresholds.runtime}min` : theme.dim('N/A'),
+        const port = action.proxmoxPort || 8006;
-      triggerMode: theme.dim(action.triggerMode || 'onlyThresholds'),
+        details = `${host}:${port}`;
-      delay: `${action.shutdownDelay || 5}s`,
+      } else if (action.type === 'webhook') {
-    }));
+        details = action.webhookUrl || theme.dim('N/A');
+      } else if (action.type === 'script') {
+        details = action.scriptPath || theme.dim('N/A');
+      }
+
+      return {
+        index: theme.dim(index.toString()),
+        type: theme.highlight(action.type),
+        battery: action.thresholds ? `${action.thresholds.battery}%` : theme.dim('N/A'),
+        runtime: action.thresholds ? `${action.thresholds.runtime}min` : theme.dim('N/A'),
+        triggerMode: theme.dim(action.triggerMode || 'onlyThresholds'),
+        details,
+      };
+    });
 
     logger.logTable(columns, rows);
     logger.log('');

ts/cli/service-handler.ts

@@ -1,7 +1,12 @@
 import process from 'node:process';
+import * as fs from 'node:fs';
+import * as path from 'node:path';
 import { execSync } from 'node:child_process';
 import { Nupst } from '../nupst.ts';
 import { logger } from '../logger.ts';
+import { theme } from '../colors.ts';
+import { PAUSE } from '../constants.ts';
+import type { IPauseState } from '../daemon.ts';
 import * as helpers from '../helpers/index.ts';
 
 /**
@@ -104,6 +109,125 @@ export class ServiceHandler {
     await this.nupst.getSystemd().getStatus(debugOptions.debugMode);
   }
 
+  /**
+   * Pause action monitoring
+   * @param args Command arguments (e.g., ['--duration', '30m'])
+   */
+  public async pause(args: string[]): Promise<void> {
+    try {
+      // Parse --duration argument
+      let resumeAt: number | null = null;
+      const durationIdx = args.indexOf('--duration');
+      if (durationIdx !== -1 && args[durationIdx + 1]) {
+        const durationStr = args[durationIdx + 1];
+        const durationMs = this.parseDuration(durationStr);
+        if (durationMs === null) {
+          logger.error(`Invalid duration format: ${durationStr}`);
+          logger.dim('  Valid formats: 30m, 2h, 1d (minutes, hours, days)');
+          return;
+        }
+        if (durationMs > PAUSE.MAX_DURATION_MS) {
+          logger.error(`Duration exceeds maximum of 24 hours`);
+          return;
+        }
+        resumeAt = Date.now() + durationMs;
+      }
+
+      // Check if already paused
+      if (fs.existsSync(PAUSE.FILE_PATH)) {
+        logger.warn('Monitoring is already paused');
+        try {
+          const data = fs.readFileSync(PAUSE.FILE_PATH, 'utf8');
+          const state = JSON.parse(data) as IPauseState;
+          logger.dim(`  Paused at: ${new Date(state.pausedAt).toISOString()}`);
+          if (state.resumeAt) {
+            const remaining = Math.round((state.resumeAt - Date.now()) / 1000);
+            logger.dim(`  Auto-resume in: ${remaining > 0 ? remaining : 0} seconds`);
+          }
+        } catch (_e) {
+          // Ignore parse errors
+        }
+        logger.dim('  Run "nupst resume" to resume monitoring');
+        return;
+      }
+
+      // Create pause state
+      const pauseState: IPauseState = {
+        pausedAt: Date.now(),
+        pausedBy: 'cli',
+        resumeAt,
+      };
+
+      // Ensure config directory exists
+      const pauseDir = path.dirname(PAUSE.FILE_PATH);
+      if (!fs.existsSync(pauseDir)) {
+        fs.mkdirSync(pauseDir, { recursive: true });
+      }
+
+      fs.writeFileSync(PAUSE.FILE_PATH, JSON.stringify(pauseState, null, 2));
+
+      logger.log('');
+      logger.logBoxTitle('Monitoring Paused', 45, 'warning');
+      logger.logBoxLine('UPS polling continues but actions are suppressed');
+      if (resumeAt) {
+        const durationStr = args[args.indexOf('--duration') + 1];
+        logger.logBoxLine(`Auto-resume after: ${durationStr}`);
+        logger.logBoxLine(`Resume at: ${new Date(resumeAt).toISOString()}`);
+      } else {
+        logger.logBoxLine('Duration: Indefinite');
+        logger.logBoxLine('Run "nupst resume" to resume');
+      }
+      logger.logBoxEnd();
+      logger.log('');
+    } catch (error) {
+      logger.error(
+        `Failed to pause: ${error instanceof Error ? error.message : String(error)}`,
+      );
+    }
+  }
+
+  /**
+   * Resume action monitoring
+   */
+  public async resume(): Promise<void> {
+    try {
+      if (!fs.existsSync(PAUSE.FILE_PATH)) {
+        logger.info('Monitoring is not paused');
+        return;
+      }
+
+      fs.unlinkSync(PAUSE.FILE_PATH);
+
+      logger.log('');
+      logger.logBoxTitle('Monitoring Resumed', 45, 'success');
+      logger.logBoxLine('Action monitoring has been resumed');
+      logger.logBoxEnd();
+      logger.log('');
+    } catch (error) {
+      logger.error(
+        `Failed to resume: ${error instanceof Error ? error.message : String(error)}`,
+      );
+    }
+  }
+
+  /**
+   * Parse a duration string like '30m', '2h', '1d' into milliseconds
+   */
+  private parseDuration(duration: string): number | null {
+    const match = duration.match(/^(\d+)\s*(m|h|d)$/i);
+    if (!match) return null;
+
+    const value = parseInt(match[1], 10);
+    const unit = match[2].toLowerCase();
+
+    switch (unit) {
+      case 'm': return value * 60 * 1000;
+      case 'h': return value * 60 * 60 * 1000;
+      case 'd': return value * 24 * 60 * 60 * 1000;
+      default: return null;
+    }
+  }
+
   /**
    * Disable the service (requires root)
    */

ts/cli/ups-handler.ts

@@ -5,8 +5,11 @@ import { type ITableColumn, logger } from '../logger.ts';
 import { theme } from '../colors.ts';
 import * as helpers from '../helpers/index.ts';
 import type { ISnmpConfig, IUpsStatus as ISnmpUpsStatus, TUpsModel } from '../snmp/types.ts';
+import type { IUpsdConfig } from '../upsd/types.ts';
+import type { TProtocol } from '../protocol/types.ts';
 import type { INupstConfig, IUpsConfig } from '../daemon.ts';
 import type { IActionConfig } from '../actions/base-action.ts';
+import { UPSD } from '../constants.ts';
 
 /**
  * Thresholds configuration for CLI display
@@ -89,31 +92,46 @@ export class UpsHandler {
     const upsId = helpers.shortId();
     const name = await prompt('UPS Name: ');
 
+    // Select protocol
+    logger.log('');
+    logger.info('Communication Protocol:');
+    logger.dim('  1) SNMP (network UPS with SNMP agent)');
+    logger.dim('  2) UPSD/NIS (local NUT server, e.g. USB-connected UPS)');
+    const protocolInput = await prompt('Select protocol [1]: ');
+    const protocolChoice = parseInt(protocolInput, 10) || 1;
+    const protocol: TProtocol = protocolChoice === 2 ? 'upsd' : 'snmp';
+
     // Create a new UPS configuration object with defaults
-    const newUps = {
+    const newUps: Record<string, unknown> & { id: string; name: string; groups: string[]; actions: IActionConfig[]; protocol: TProtocol; snmp?: ISnmpConfig; upsd?: IUpsdConfig } = {
       id: upsId,
       name: name || `UPS-${upsId}`,
-      snmp: {
+      protocol,
+      groups: [],
+      actions: [],
+    };
+
+    if (protocol === 'snmp') {
+      newUps.snmp = {
         host: '127.0.0.1',
         port: 161,
         community: 'public',
         version: 1,
         timeout: 5000,
         upsModel: 'cyberpower' as TUpsModel,
-      },
+      };
-      thresholds: {
+      // Gather SNMP settings
-        battery: 60,
+      await this.gatherSnmpSettings(newUps.snmp, prompt);
-        runtime: 20,
+      // Gather UPS model settings
-      },
+      await this.gatherUpsModelSettings(newUps.snmp, prompt);
-      groups: [],
+    } else {
-      actions: [],
+      newUps.upsd = {
-    };
+        host: '127.0.0.1',
-
+        port: UPSD.DEFAULT_PORT,
-    // Gather SNMP settings
+        upsName: UPSD.DEFAULT_UPS_NAME,
-    await this.gatherSnmpSettings(newUps.snmp, prompt);
+        timeout: UPSD.DEFAULT_TIMEOUT_MS,
-
+      };
-    // Gather UPS model settings
+      await this.gatherUpsdSettings(newUps.upsd, prompt);
-    await this.gatherUpsModelSettings(newUps.snmp, prompt);
+    }
 
     // Get access to GroupHandler for group assignments
     const groupHandler = this.nupst.getGroupHandler();
@@ -132,10 +150,14 @@ export class UpsHandler {
     // Save the configuration
     await this.nupst.getDaemon().saveConfig(config as INupstConfig);
 
-    this.displayUpsConfigSummary(newUps);
+    this.displayUpsConfigSummary(newUps as unknown as IUpsConfig);
 
     // Test the connection if requested
-    await this.optionallyTestConnection(newUps.snmp, prompt);
+    if (protocol === 'snmp' && newUps.snmp) {
+      await this.optionallyTestConnection(newUps.snmp as ISnmpConfig, prompt);
+    } else if (protocol === 'upsd' && newUps.upsd) {
+      await this.optionallyTestUpsdConnection(newUps.upsd, prompt);
+    }
 
     // Check if service is running and restart it if needed
     await this.restartServiceIfRunning();
@@ -232,11 +254,51 @@ export class UpsHandler {
       upsToEdit.name = newName;
     }
 
-    // Edit SNMP settings
+    // Show current protocol and allow changing
-    await this.gatherSnmpSettings(upsToEdit.snmp, prompt);
+    const currentProtocol = upsToEdit.protocol || 'snmp';
+    logger.log('');
+    logger.info(`Current Protocol: ${currentProtocol.toUpperCase()}`);
+    logger.dim('  1) SNMP (network UPS with SNMP agent)');
+    logger.dim('  2) UPSD/NIS (local NUT server, e.g. USB-connected UPS)');
+    const protocolInput = await prompt(`Select protocol [${currentProtocol === 'upsd' ? '2' : '1'}]: `);
+    const protocolChoice = parseInt(protocolInput, 10);
+    if (protocolChoice === 2) {
+      upsToEdit.protocol = 'upsd';
+    } else if (protocolChoice === 1) {
+      upsToEdit.protocol = 'snmp';
+    }
+    // else keep current
 
-    // Edit UPS model settings
+    const editProtocol = upsToEdit.protocol || 'snmp';
-    await this.gatherUpsModelSettings(upsToEdit.snmp, prompt);
+
+    if (editProtocol === 'snmp') {
+      // Initialize SNMP config if switching from UPSD
+      if (!upsToEdit.snmp) {
+        upsToEdit.snmp = {
+          host: '127.0.0.1',
+          port: 161,
+          community: 'public',
+          version: 1,
+          timeout: 5000,
+          upsModel: 'cyberpower' as TUpsModel,
+        };
+      }
+      // Edit SNMP settings
+      await this.gatherSnmpSettings(upsToEdit.snmp, prompt);
+      // Edit UPS model settings
+      await this.gatherUpsModelSettings(upsToEdit.snmp, prompt);
+    } else {
+      // Initialize UPSD config if switching from SNMP
+      if (!upsToEdit.upsd) {
+        upsToEdit.upsd = {
+          host: '127.0.0.1',
+          port: UPSD.DEFAULT_PORT,
+          upsName: UPSD.DEFAULT_UPS_NAME,
+          timeout: UPSD.DEFAULT_TIMEOUT_MS,
+        };
+      }
+      await this.gatherUpsdSettings(upsToEdit.upsd, prompt);
+    }
 
     // Get access to GroupHandler for group assignments
     const groupHandler = this.nupst.getGroupHandler();
@@ -260,7 +322,11 @@ export class UpsHandler {
     this.displayUpsConfigSummary(upsToEdit);
 
     // Test the connection if requested
-    await this.optionallyTestConnection(upsToEdit.snmp, prompt);
+    if (editProtocol === 'snmp' && upsToEdit.snmp) {
+      await this.optionallyTestConnection(upsToEdit.snmp, prompt);
+    } else if (editProtocol === 'upsd' && upsToEdit.upsd) {
+      await this.optionallyTestUpsdConnection(upsToEdit.upsd, prompt);
+    }
 
     // Check if service is running and restart it if needed
     await this.restartServiceIfRunning();
@@ -397,17 +463,31 @@ export class UpsHandler {
       }
 
       // Prepare table data
-      const rows = config.upsDevices.map((ups) => ({
+      const rows = config.upsDevices.map((ups) => {
-        id: ups.id,
+        const protocol = ups.protocol || 'snmp';
-        name: ups.name || '',
+        let host = 'N/A';
-        host: `${ups.snmp.host}:${ups.snmp.port}`,
+        let model = '';
-        model: ups.snmp.upsModel || 'cyberpower',
+        if (protocol === 'upsd' && ups.upsd) {
-        groups: ups.groups.length > 0 ? ups.groups.join(', ') : theme.dim('None'),
+          host = `${ups.upsd.host}:${ups.upsd.port}`;
-      }));
+          model = `NUT:${ups.upsd.upsName}`;
+        } else if (ups.snmp) {
+          host = `${ups.snmp.host}:${ups.snmp.port}`;
+          model = ups.snmp.upsModel || 'cyberpower';
+        }
+        return {
+          id: ups.id,
+          name: ups.name || '',
+          protocol: protocol.toUpperCase(),
+          host,
+          model,
+          groups: ups.groups.length > 0 ? ups.groups.join(', ') : theme.dim('None'),
+        };
+      });
 
       const columns: ITableColumn[] = [
         { header: 'ID', key: 'id', align: 'left', color: theme.highlight },
         { header: 'Name', key: 'name', align: 'left' },
+        { header: 'Protocol', key: 'protocol', align: 'left' },
         { header: 'Host:Port', key: 'host', align: 'left', color: theme.info },
         { header: 'Model', key: 'model', align: 'left' },
         { header: 'Groups', key: 'groups', align: 'left' },
@@ -482,58 +562,71 @@ export class UpsHandler {
     // Type guard: IUpsConfig has 'id' and 'name' at root level, INupstConfig doesn't
     const isUpsConfig = 'id' in config && 'name' in config;
 
-    // Get SNMP config and other values based on config type
-    const snmpConfig: ISnmpConfig | undefined = isUpsConfig
-      ? (config as IUpsConfig).snmp
-      : (config as INupstConfig).snmp;
     const checkInterval = isUpsConfig ? 30000 : (config as INupstConfig).checkInterval || 30000;
     const upsName = isUpsConfig ? (config as IUpsConfig).name : 'Default UPS';
     const upsId = isUpsConfig ? (config as IUpsConfig).id : 'default';
+    const protocol = isUpsConfig ? ((config as IUpsConfig).protocol || 'snmp') : 'snmp';
 
     const boxWidth = 45;
     logger.logBoxTitle(`Testing Configuration: ${upsName}`, boxWidth);
     logger.logBoxLine(`UPS ID: ${upsId}`);
+    logger.logBoxLine(`Protocol: ${protocol.toUpperCase()}`);
 
-    if (!snmpConfig) {
+    if (protocol === 'upsd' && isUpsConfig && (config as IUpsConfig).upsd) {
-      logger.logBoxLine('SNMP Settings: Not configured');
+      const upsdConfig = (config as IUpsConfig).upsd!;
-      logger.logBoxEnd();
+      logger.logBoxLine('UPSD/NIS Settings:');
-      return;
+      logger.logBoxLine(`  Host: ${upsdConfig.host}`);
-    }
+      logger.logBoxLine(`  Port: ${upsdConfig.port}`);
+      logger.logBoxLine(`  UPS Name: ${upsdConfig.upsName}`);
+      logger.logBoxLine(`  Timeout: ${upsdConfig.timeout / 1000} seconds`);
+      if (upsdConfig.username) {
+        logger.logBoxLine(`  Auth: ${upsdConfig.username}`);
+      }
+    } else {
+      // SNMP display
+      const snmpConfig: ISnmpConfig | undefined = isUpsConfig
+        ? (config as IUpsConfig).snmp
+        : (config as INupstConfig).snmp;
 
-    logger.logBoxLine('SNMP Settings:');
+      if (!snmpConfig) {
-    logger.logBoxLine(`  Host: ${snmpConfig.host}`);
+        logger.logBoxLine('SNMP Settings: Not configured');
-    logger.logBoxLine(`  Port: ${snmpConfig.port}`);
+        logger.logBoxEnd();
-    logger.logBoxLine(`  Version: ${snmpConfig.version}`);
+        return;
-    logger.logBoxLine(`  UPS Model: ${snmpConfig.upsModel || 'cyberpower'}`);
-
-    if (snmpConfig.version === 1 || snmpConfig.version === 2) {
-      logger.logBoxLine(`  Community: ${snmpConfig.community}`);
-    } else if (snmpConfig.version === 3) {
-      logger.logBoxLine(`  Security Level: ${snmpConfig.securityLevel}`);
-      logger.logBoxLine(`  Username: ${snmpConfig.username}`);
-
-      // Show auth and privacy details based on security level
-      if (snmpConfig.securityLevel === 'authNoPriv' || snmpConfig.securityLevel === 'authPriv') {
-        logger.logBoxLine(`  Auth Protocol: ${snmpConfig.authProtocol || 'None'}`);
       }
 
-      if (snmpConfig.securityLevel === 'authPriv') {
+      logger.logBoxLine('SNMP Settings:');
-        logger.logBoxLine(`  Privacy Protocol: ${snmpConfig.privProtocol || 'None'}`);
+      logger.logBoxLine(`  Host: ${snmpConfig.host}`);
+      logger.logBoxLine(`  Port: ${snmpConfig.port}`);
+      logger.logBoxLine(`  Version: ${snmpConfig.version}`);
+      logger.logBoxLine(`  UPS Model: ${snmpConfig.upsModel || 'cyberpower'}`);
+
+      if (snmpConfig.version === 1 || snmpConfig.version === 2) {
+        logger.logBoxLine(`  Community: ${snmpConfig.community}`);
+      } else if (snmpConfig.version === 3) {
+        logger.logBoxLine(`  Security Level: ${snmpConfig.securityLevel}`);
+        logger.logBoxLine(`  Username: ${snmpConfig.username}`);
+
+        if (snmpConfig.securityLevel === 'authNoPriv' || snmpConfig.securityLevel === 'authPriv') {
+          logger.logBoxLine(`  Auth Protocol: ${snmpConfig.authProtocol || 'None'}`);
+        }
+
+        if (snmpConfig.securityLevel === 'authPriv') {
+          logger.logBoxLine(`  Privacy Protocol: ${snmpConfig.privProtocol || 'None'}`);
+        }
+
+        logger.logBoxLine(`  Timeout: ${snmpConfig.timeout / 1000} seconds`);
       }
 
-      // Show timeout value
+      if (snmpConfig.upsModel === 'custom' && snmpConfig.customOIDs) {
-      logger.logBoxLine(`  Timeout: ${snmpConfig.timeout / 1000} seconds`);
+        logger.logBoxLine('Custom OIDs:');
+        logger.logBoxLine(`  Power Status: ${snmpConfig.customOIDs.POWER_STATUS || 'Not set'}`);
+        logger.logBoxLine(
+          `  Battery Capacity: ${snmpConfig.customOIDs.BATTERY_CAPACITY || 'Not set'}`,
+        );
+        logger.logBoxLine(`  Battery Runtime: ${snmpConfig.customOIDs.BATTERY_RUNTIME || 'Not set'}`);
+      }
     }
 
-    // Show OIDs if custom model is selected
-    if (snmpConfig.upsModel === 'custom' && snmpConfig.customOIDs) {
-      logger.logBoxLine('Custom OIDs:');
-      logger.logBoxLine(`  Power Status: ${snmpConfig.customOIDs.POWER_STATUS || 'Not set'}`);
-      logger.logBoxLine(
-        `  Battery Capacity: ${snmpConfig.customOIDs.BATTERY_CAPACITY || 'Not set'}`,
-      );
-      logger.logBoxLine(`  Battery Runtime: ${snmpConfig.customOIDs.BATTERY_RUNTIME || 'Not set'}`);
-    }
     // Show group assignments if this is a UPS config
     if (isUpsConfig) {
       const groups = (config as IUpsConfig).groups;
@@ -555,25 +648,36 @@ export class UpsHandler {
     const isUpsConfig = 'id' in config && 'name' in config;
     const upsId = isUpsConfig ? (config as IUpsConfig).id : 'default';
     const upsName = isUpsConfig ? (config as IUpsConfig).name : 'Default UPS';
-    logger.log(`\nTesting connection to UPS: ${upsName} (${upsId})...`);
+    const protocol = isUpsConfig ? ((config as IUpsConfig).protocol || 'snmp') : 'snmp';
+    logger.log(`\nTesting connection to UPS: ${upsName} (${upsId}) via ${protocol.toUpperCase()}...`);
 
     try {
-      // Get SNMP config based on config type
+      let status: ISnmpUpsStatus;
-      const snmpConfig: ISnmpConfig | undefined = isUpsConfig
-        ? (config as IUpsConfig).snmp
-        : (config as INupstConfig).snmp;
 
-      if (!snmpConfig) {
+      if (protocol === 'upsd' && isUpsConfig && (config as IUpsConfig).upsd) {
-        throw new Error('SNMP configuration not found');
+        const upsdConfig = (config as IUpsConfig).upsd!;
+        const testConfig = {
+          ...upsdConfig,
+          timeout: Math.min(upsdConfig.timeout, 10000),
+        };
+        status = await this.nupst.getUpsd().getUpsStatus(testConfig);
+      } else {
+        // SNMP protocol
+        const snmpConfig: ISnmpConfig | undefined = isUpsConfig
+          ? (config as IUpsConfig).snmp
+          : (config as INupstConfig).snmp;
+
+        if (!snmpConfig) {
+          throw new Error('SNMP configuration not found');
+        }
+
+        const testConfig: ISnmpConfig = {
+          ...snmpConfig,
+          timeout: Math.min(snmpConfig.timeout, 10000),
+        };
+        status = await this.nupst.getSnmp().getUpsStatus(testConfig);
       }
 
-      const testConfig: ISnmpConfig = {
-        ...snmpConfig,
-        timeout: Math.min(snmpConfig.timeout, 10000), // Use at most 10 seconds for testing
-      };
-
-      const status = await this.nupst.getSnmp().getUpsStatus(testConfig);
-
       const boxWidth = 45;
       logger.logBoxTitle(`Connection Successful: ${upsName}`, boxWidth);
       logger.logBoxLine('UPS Status:');
@@ -872,6 +976,97 @@ export class UpsHandler {
     }
   }
 
+  /**
+   * Gather UPSD/NIS connection settings
+   * @param upsdConfig UPSD configuration object to update
+   * @param prompt Function to prompt for user input
+   */
+  private async gatherUpsdSettings(
+    upsdConfig: IUpsdConfig,
+    prompt: (question: string) => Promise<string>,
+  ): Promise<void> {
+    logger.log('');
+    logger.info('UPSD/NIS Connection Settings:');
+    logger.dim('Connect to a local NUT (Network UPS Tools) server');
+
+    // Host
+    const defaultHost = upsdConfig.host || '127.0.0.1';
+    const host = await prompt(`UPSD Host [${defaultHost}]: `);
+    upsdConfig.host = host.trim() || defaultHost;
+
+    // Port
+    const defaultPort = upsdConfig.port || UPSD.DEFAULT_PORT;
+    const portInput = await prompt(`UPSD Port [${defaultPort}]: `);
+    const port = parseInt(portInput, 10);
+    upsdConfig.port = portInput.trim() && !isNaN(port) ? port : defaultPort;
+
+    // UPS Name
+    const defaultUpsName = upsdConfig.upsName || UPSD.DEFAULT_UPS_NAME;
+    const upsName = await prompt(`NUT UPS Name [${defaultUpsName}]: `);
+    upsdConfig.upsName = upsName.trim() || defaultUpsName;
+
+    // Timeout
+    const defaultTimeout = (upsdConfig.timeout || UPSD.DEFAULT_TIMEOUT_MS) / 1000;
+    const timeoutInput = await prompt(`Timeout in seconds [${defaultTimeout}]: `);
+    const timeout = parseInt(timeoutInput, 10);
+    if (timeoutInput.trim() && !isNaN(timeout)) {
+      upsdConfig.timeout = timeout * 1000;
+    }
+
+    // Authentication (optional)
+    logger.log('');
+    logger.info('Authentication (optional):');
+    logger.dim('Leave blank if your NUT server does not require authentication');
+    const username = await prompt(`Username [${upsdConfig.username || ''}]: `);
+    if (username.trim()) {
+      upsdConfig.username = username.trim();
+      const password = await prompt(`Password: `);
+      if (password.trim()) {
+        upsdConfig.password = password.trim();
+      }
+    }
+  }
+
+  /**
+   * Optionally test UPSD connection
+   * @param upsdConfig UPSD configuration to test
+   * @param prompt Function to prompt for user input
+   */
+  private async optionallyTestUpsdConnection(
+    upsdConfig: IUpsdConfig,
+    prompt: (question: string) => Promise<string>,
+  ): Promise<void> {
+    const testConnection = await prompt(
+      'Would you like to test the connection to your UPS? (y/N): ',
+    );
+    if (testConnection.toLowerCase() === 'y') {
+      logger.log('\nTesting connection to UPSD server...');
+      try {
+        const testConfig = {
+          ...upsdConfig,
+          timeout: Math.min(upsdConfig.timeout, 10000),
+        };
+
+        const status = await this.nupst.getUpsd().getUpsStatus(testConfig);
+        const boxWidth = 45;
+        logger.log('');
+        logger.logBoxTitle('Connection Successful!', boxWidth);
+        logger.logBoxLine('UPS Status:');
+        logger.logBoxLine(`✓ Power Status: ${status.powerStatus}`);
+        logger.logBoxLine(`✓ Battery Capacity: ${status.batteryCapacity}%`);
+        logger.logBoxLine(`✓ Runtime Remaining: ${status.batteryRuntime} minutes`);
+        logger.logBoxEnd();
+      } catch (error) {
+        const errorBoxWidth = 45;
+        logger.log('');
+        logger.logBoxTitle('Connection Failed!', errorBoxWidth);
+        logger.logBoxLine(`Error: ${error instanceof Error ? error.message : String(error)}`);
+        logger.logBoxEnd();
+        logger.log('\nPlease check your NUT server settings and try again.');
+      }
+    }
+  }
+
   /**
    * Gather action configuration settings
    * @param actions Actions array to configure
@@ -901,6 +1096,7 @@ export class UpsHandler {
       logger.dim('  1) Shutdown (system shutdown)');
       logger.dim('  2) Webhook (HTTP notification)');
       logger.dim('  3) Custom Script (run .sh file from /etc/nupst)');
+      logger.dim('  4) Proxmox (gracefully shut down VMs/LXCs before host shutdown)');
 
       const typeInput = await prompt('Select action type [1]: ');
       const typeValue = parseInt(typeInput, 10) || 1;
@@ -955,6 +1151,61 @@ export class UpsHandler {
         if (timeoutInput.trim() && !isNaN(timeout)) {
           action.scriptTimeout = timeout * 1000; // Convert to ms
         }
+      } else if (typeValue === 4) {
+        // Proxmox action
+        action.type = 'proxmox';
+
+        logger.log('');
+        logger.info('Proxmox API Settings:');
+        logger.dim('Requires a Proxmox API token. Create one with:');
+        logger.dim('  pveum user token add root@pam nupst --privsep=0');
+
+        const pxHost = await prompt('Proxmox Host [localhost]: ');
+        action.proxmoxHost = pxHost.trim() || 'localhost';
+
+        const pxPortInput = await prompt('Proxmox API Port [8006]: ');
+        const pxPort = parseInt(pxPortInput, 10);
+        action.proxmoxPort = pxPortInput.trim() && !isNaN(pxPort) ? pxPort : 8006;
+
+        const pxNode = await prompt('Proxmox Node Name (empty = auto-detect via hostname): ');
+        if (pxNode.trim()) {
+          action.proxmoxNode = pxNode.trim();
+        }
+
+        const tokenId = await prompt('API Token ID (e.g., root@pam!nupst): ');
+        if (!tokenId.trim()) {
+          logger.warn('Token ID is required for Proxmox action, skipping');
+          continue;
+        }
+        action.proxmoxTokenId = tokenId.trim();
+
+        const tokenSecret = await prompt('API Token Secret: ');
+        if (!tokenSecret.trim()) {
+          logger.warn('Token Secret is required for Proxmox action, skipping');
+          continue;
+        }
+        action.proxmoxTokenSecret = tokenSecret.trim();
+
+        const excludeInput = await prompt('VM/CT IDs to exclude (comma-separated, or empty): ');
+        if (excludeInput.trim()) {
+          action.proxmoxExcludeIds = excludeInput.split(',').map((s) => parseInt(s.trim(), 10)).filter((n) => !isNaN(n));
+        }
+
+        const timeoutInput = await prompt('VM shutdown timeout in seconds [120]: ');
+        const stopTimeout = parseInt(timeoutInput, 10);
+        if (timeoutInput.trim() && !isNaN(stopTimeout)) {
+          action.proxmoxStopTimeout = stopTimeout;
+        }
+
+        const forceInput = await prompt('Force-stop VMs that don\'t shut down in time? (Y/n): ');
+        action.proxmoxForceStop = forceInput.toLowerCase() !== 'n';
+
+        const insecureInput = await prompt('Skip TLS verification (self-signed cert)? (Y/n): ');
+        action.proxmoxInsecure = insecureInput.toLowerCase() !== 'n';
+
+        logger.log('');
+        logger.info('Note: Place the Proxmox action BEFORE the shutdown action');
+        logger.dim('in the action chain so VMs shut down before the host.');
       } else {
         logger.warn('Invalid action type, skipping');
         continue;
@@ -1032,12 +1283,20 @@ export class UpsHandler {
    */
   private displayUpsConfigSummary(ups: IUpsConfig): void {
     const boxWidth = 45;
+    const protocol = ups.protocol || 'snmp';
     logger.log('');
     logger.logBoxTitle(`UPS Configuration: ${ups.name}`, boxWidth);
     logger.logBoxLine(`UPS ID: ${ups.id}`);
-    logger.logBoxLine(`SNMP Host: ${ups.snmp.host}:${ups.snmp.port}`);
+    logger.logBoxLine(`Protocol: ${protocol.toUpperCase()}`);
-    logger.logBoxLine(`SNMP Version: ${ups.snmp.version}`);
+
-    logger.logBoxLine(`UPS Model: ${ups.snmp.upsModel}`);
+    if (protocol === 'upsd' && ups.upsd) {
+      logger.logBoxLine(`UPSD Host: ${ups.upsd.host}:${ups.upsd.port}`);
+      logger.logBoxLine(`NUT UPS Name: ${ups.upsd.upsName}`);
+    } else if (ups.snmp) {
+      logger.logBoxLine(`SNMP Host: ${ups.snmp.host}:${ups.snmp.port}`);
+      logger.logBoxLine(`SNMP Version: ${ups.snmp.version}`);
+      logger.logBoxLine(`UPS Model: ${ups.snmp.upsModel}`);
+    }
 
     if (ups.groups && ups.groups.length > 0) {
       logger.logBoxLine(`Groups: ${ups.groups.join(', ')}`);

ts/colors.ts

@@ -75,12 +75,14 @@ export function getRuntimeColor(minutes: number): (text: string) => string {
 /**
  * Format UPS power status with color
  */
-export function formatPowerStatus(status: 'online' | 'onBattery' | 'unknown'): string {
+export function formatPowerStatus(status: 'online' | 'onBattery' | 'unknown' | 'unreachable'): string {
   switch (status) {
     case 'online':
       return theme.success('Online');
     case 'onBattery':
       return theme.warning('On Battery');
+    case 'unreachable':
+      return theme.error('Unreachable');
     case 'unknown':
     default:
       return theme.dim('Unknown');

ts/constants.ts

@@ -103,6 +103,62 @@ export const HTTP_SERVER = {
   DEFAULT_PATH: '/ups-status',
 } as const;
 
+/**
+ * Network failure detection constants
+ */
+export const NETWORK = {
+  /** Number of consecutive failures before marking UPS as unreachable */
+  CONSECUTIVE_FAILURE_THRESHOLD: 3,
+
+  /** Maximum tracked consecutive failures (prevents overflow) */
+  MAX_CONSECUTIVE_FAILURES: 100,
+} as const;
+
+/**
+ * UPSD/NIS protocol constants
+ */
+export const UPSD = {
+  /** Default UPSD port (NUT standard) */
+  DEFAULT_PORT: 3493,
+
+  /** Default timeout in milliseconds */
+  DEFAULT_TIMEOUT_MS: 5000,
+
+  /** Default NUT device name */
+  DEFAULT_UPS_NAME: 'ups',
+} as const;
+
+/**
+ * Pause/resume constants
+ */
+export const PAUSE = {
+  /** Path to the pause state file */
+  FILE_PATH: '/etc/nupst/pause',
+
+  /** Maximum pause duration (24 hours) */
+  MAX_DURATION_MS: 24 * 60 * 60 * 1000,
+} as const;
+
+/**
+ * Proxmox VM shutdown constants
+ */
+export const PROXMOX = {
+  /** Default Proxmox API port */
+  DEFAULT_PORT: 8006,
+
+  /** Default Proxmox host */
+  DEFAULT_HOST: 'localhost',
+
+  /** Default timeout for VM/CT shutdown in seconds */
+  DEFAULT_STOP_TIMEOUT_SECONDS: 120,
+
+  /** Poll interval for checking VM/CT status in seconds */
+  STATUS_POLL_INTERVAL_SECONDS: 5,
+
+  /** Proxmox API base path */
+  API_BASE: '/api2/json',
+} as const;
+
 /**
  * UI/Display constants
  */

ts/daemon.ts

@@ -5,13 +5,17 @@ import { exec, execFile } from 'node:child_process';
 import { promisify } from 'node:util';
 import { NupstSnmp } from './snmp/manager.ts';
 import type { ISnmpConfig, IUpsStatus as ISnmpUpsStatus } from './snmp/types.ts';
+import { NupstUpsd } from './upsd/client.ts';
+import type { IUpsdConfig } from './upsd/types.ts';
+import type { TProtocol } from './protocol/types.ts';
+import { ProtocolResolver } from './protocol/resolver.ts';
 import { logger } from './logger.ts';
 import { MigrationRunner } from './migrations/index.ts';
 import { formatPowerStatus, getBatteryColor, getRuntimeColor, theme } from './colors.ts';
 import type { IActionConfig } from './actions/base-action.ts';
 import { ActionManager, type IActionContext, type TPowerStatus } from './actions/index.ts';
 import { NupstHttpServer } from './http-server.ts';
-import { THRESHOLDS, TIMING, UI } from './constants.ts';
+import { NETWORK, PAUSE, THRESHOLDS, TIMING, UI } from './constants.ts';
 
 const execAsync = promisify(exec);
 const execFileAsync = promisify(execFile);
@@ -24,8 +28,12 @@ export interface IUpsConfig {
   id: string;
   /** Friendly name for the UPS */
   name: string;
-  /** SNMP configuration settings */
+  /** Communication protocol (defaults to 'snmp') */
-  snmp: ISnmpConfig;
+  protocol?: TProtocol;
+  /** SNMP configuration settings (required for 'snmp' protocol) */
+  snmp?: ISnmpConfig;
+  /** UPSD/NIS configuration settings (required for 'upsd' protocol) */
+  upsd?: IUpsdConfig;
   /** Group IDs this UPS belongs to */
   groups: string[];
   /** Actions to trigger on power status changes and threshold violations */
@@ -62,6 +70,20 @@ export interface IHttpServerConfig {
   authToken: string;
 }
 
+/**
+ * Pause state interface
+ */
+export interface IPauseState {
+  /** Timestamp when pause was activated */
+  pausedAt: number;
+  /** Who initiated the pause (e.g., 'cli', 'api') */
+  pausedBy: string;
+  /** Optional reason for pausing */
+  reason?: string;
+  /** When to auto-resume (null = indefinite, timestamp in ms) */
+  resumeAt?: number | null;
+}
+
 /**
  * Configuration interface for the daemon
  */
@@ -97,7 +119,7 @@ export interface INupstConfig {
 export interface IUpsStatus {
   id: string;
   name: string;
-  powerStatus: 'online' | 'onBattery' | 'unknown';
+  powerStatus: 'online' | 'onBattery' | 'unknown' | 'unreachable';
   batteryCapacity: number;
   batteryRuntime: number;
   outputLoad: number; // Load percentage (0-100%)
@@ -106,6 +128,8 @@ export interface IUpsStatus {
   outputCurrent: number; // Current in amps
   lastStatusChange: number;
   lastCheckTime: number;
+  consecutiveFailures: number;
+  unreachableSince: number;
 }
 
 /**
@@ -159,15 +183,21 @@ export class NupstDaemon {
 
   private config: INupstConfig;
   private snmp: NupstSnmp;
+  private upsd: NupstUpsd;
+  private protocolResolver: ProtocolResolver;
   private isRunning: boolean = false;
+  private isPaused: boolean = false;
+  private pauseState: IPauseState | null = null;
   private upsStatus: Map<string, IUpsStatus> = new Map();
   private httpServer?: NupstHttpServer;
 
   /**
-   * Create a new daemon instance with the given SNMP manager
+   * Create a new daemon instance with the given protocol managers
    */
-  constructor(snmp: NupstSnmp) {
+  constructor(snmp: NupstSnmp, upsd: NupstUpsd) {
     this.snmp = snmp;
+    this.upsd = upsd;
+    this.protocolResolver = new ProtocolResolver(snmp, upsd);
     this.config = this.DEFAULT_CONFIG;
   }
 
@@ -230,10 +260,11 @@ export class NupstDaemon {
 
       // Ensure version is always set and remove legacy fields before saving
       const configToSave: INupstConfig = {
-        version: '4.1',
+        version: '4.2',
         upsDevices: config.upsDevices,
         groups: config.groups,
         checkInterval: config.checkInterval,
+        ...(config.httpServer ? { httpServer: config.httpServer } : {}),
       };
 
       fs.writeFileSync(this.CONFIG_PATH, JSON.stringify(configToSave, null, 2));
@@ -271,6 +302,13 @@ export class NupstDaemon {
     return this.snmp;
   }
 
+  /**
+   * Get the UPSD instance
+   */
+  public getNupstUpsd(): NupstUpsd {
+    return this.upsd;
+  }
+
   /**
    * Start the monitoring daemon
    */
@@ -317,6 +355,7 @@ export class NupstDaemon {
             this.config.httpServer.path,
             this.config.httpServer.authToken,
             () => this.upsStatus,
+            () => this.pauseState,
           );
           this.httpServer.start();
         } catch (error) {
@@ -360,6 +399,8 @@ export class NupstDaemon {
           outputCurrent: 0,
           lastStatusChange: Date.now(),
           lastCheckTime: 0,
+          consecutiveFailures: 0,
+          unreachableSince: 0,
         });
       }
 
@@ -388,16 +429,27 @@ export class NupstDaemon {
       > = [
         { header: 'Name', key: 'name', align: 'left', color: theme.highlight },
         { header: 'ID', key: 'id', align: 'left', color: theme.dim },
+        { header: 'Protocol', key: 'protocol', align: 'left' },
         { header: 'Host:Port', key: 'host', align: 'left', color: theme.info },
         { header: 'Actions', key: 'actions', align: 'left' },
       ];
 
-      const upsRows: Array<Record<string, string>> = this.config.upsDevices.map((ups) => ({
+      const upsRows: Array<Record<string, string>> = this.config.upsDevices.map((ups) => {
-        name: ups.name,
+        const protocol = ups.protocol || 'snmp';
-        id: ups.id,
+        let host = 'N/A';
-        host: `${ups.snmp.host}:${ups.snmp.port}`,
+        if (protocol === 'upsd' && ups.upsd) {
-        actions: `${(ups.actions || []).length} configured`,
+          host = `${ups.upsd.host}:${ups.upsd.port}`;
-      }));
+        } else if (ups.snmp) {
+          host = `${ups.snmp.host}:${ups.snmp.port}`;
+        }
+        return {
+          name: ups.name,
+          id: ups.id,
+          protocol: protocol.toUpperCase(),
+          host,
+          actions: `${(ups.actions || []).length} configured`,
+        };
+      });
 
       logger.logTable(upsColumns, upsRows);
       logger.log('');
@@ -443,6 +495,79 @@ export class NupstDaemon {
     this.isRunning = false;
   }
 
+  /**
+   * Get the current pause state
+   */
+  public getPauseState(): IPauseState | null {
+    return this.pauseState;
+  }
+
+  /**
+   * Check and update pause state from the pause file
+   */
+  private checkPauseState(): void {
+    try {
+      if (fs.existsSync(PAUSE.FILE_PATH)) {
+        const data = fs.readFileSync(PAUSE.FILE_PATH, 'utf8');
+        const state = JSON.parse(data) as IPauseState;
+
+        // Check if auto-resume time has passed
+        if (state.resumeAt && Date.now() >= state.resumeAt) {
+          // Auto-resume: delete the pause file
+          try {
+            fs.unlinkSync(PAUSE.FILE_PATH);
+          } catch (_e) {
+            // Ignore deletion errors
+          }
+          if (this.isPaused) {
+            logger.log('');
+            logger.logBoxTitle('Auto-Resume', 45, 'success');
+            logger.logBoxLine('Pause duration expired, resuming action monitoring');
+            logger.logBoxEnd();
+            logger.log('');
+          }
+          this.isPaused = false;
+          this.pauseState = null;
+          return;
+        }
+
+        if (!this.isPaused) {
+          logger.log('');
+          logger.logBoxTitle('Actions Paused', 45, 'warning');
+          logger.logBoxLine(`Paused by: ${state.pausedBy}`);
+          if (state.reason) {
+            logger.logBoxLine(`Reason: ${state.reason}`);
+          }
+          if (state.resumeAt) {
+            const remaining = Math.round((state.resumeAt - Date.now()) / 1000);
+            logger.logBoxLine(`Auto-resume in: ${remaining} seconds`);
+          } else {
+            logger.logBoxLine('Duration: Indefinite (run "nupst resume" to resume)');
+          }
+          logger.logBoxEnd();
+          logger.log('');
+        }
+
+        this.isPaused = true;
+        this.pauseState = state;
+      } else {
+        if (this.isPaused) {
+          logger.log('');
+          logger.logBoxTitle('Actions Resumed', 45, 'success');
+          logger.logBoxLine('Action monitoring has been resumed');
+          logger.logBoxEnd();
+          logger.log('');
+        }
+        this.isPaused = false;
+        this.pauseState = null;
+      }
+    } catch (_error) {
+      // If we can't read the pause file, assume not paused
+      this.isPaused = false;
+      this.pauseState = null;
+    }
+  }
+
   /**
    * Monitor the UPS status and trigger shutdown when necessary
    */
@@ -461,7 +586,10 @@ export class NupstDaemon {
     // Monitor continuously
     while (this.isRunning) {
       try {
-        // Check all UPS devices
+        // Check pause state before each cycle
+        this.checkPauseState();
+
+        // Check all UPS devices (polling continues even when paused for visibility)
         await this.checkAllUpsDevices();
 
         // Log periodic status update
@@ -505,16 +633,24 @@ export class NupstDaemon {
             outputCurrent: 0,
             lastStatusChange: Date.now(),
             lastCheckTime: 0,
+            consecutiveFailures: 0,
+            unreachableSince: 0,
           });
         }
 
-        // Check UPS status
+        // Check UPS status via configured protocol
-        const status = await this.snmp.getUpsStatus(ups.snmp);
+        const protocol = ups.protocol || 'snmp';
+        const status = protocol === 'upsd' && ups.upsd
+          ? await this.protocolResolver.getUpsStatus('upsd', undefined, ups.upsd)
+          : await this.protocolResolver.getUpsStatus('snmp', ups.snmp);
         const currentTime = Date.now();
 
         // Get the current status from the map
         const currentStatus = this.upsStatus.get(ups.id);
 
+        // Successful query: reset consecutive failures
+        const wasUnreachable = currentStatus?.powerStatus === 'unreachable';
+
         // Update status with new values
         const updatedStatus: IUpsStatus = {
           id: ups.id,
@@ -528,10 +664,27 @@ export class NupstDaemon {
           outputCurrent: status.outputCurrent,
           lastCheckTime: currentTime,
           lastStatusChange: currentStatus?.lastStatusChange || currentTime,
+          consecutiveFailures: 0,
+          unreachableSince: 0,
         };
 
-        // Check if power status changed
+        // If UPS was unreachable and is now reachable, log recovery
-        if (currentStatus && currentStatus.powerStatus !== status.powerStatus) {
+        if (wasUnreachable && currentStatus) {
+          const downtime = Math.round((currentTime - currentStatus.unreachableSince) / 1000);
+          logger.log('');
+          logger.logBoxTitle(`UPS Recovered: ${ups.name}`, 60, 'success');
+          logger.logBoxLine(`UPS is reachable again after ${downtime} seconds`);
+          logger.logBoxLine(`Current Status: ${formatPowerStatus(status.powerStatus)}`);
+          logger.logBoxLine(`Time: ${new Date().toISOString()}`);
+          logger.logBoxEnd();
+          logger.log('');
+
+          updatedStatus.lastStatusChange = currentTime;
+
+          // Trigger power status change action for recovery
+          await this.triggerUpsActions(ups, updatedStatus, currentStatus, 'powerStatusChange');
+        } else if (currentStatus && currentStatus.powerStatus !== status.powerStatus) {
+          // Check if power status changed
           logger.log('');
           logger.logBoxTitle(`Power Status Change: ${ups.name}`, 60, 'warning');
           logger.logBoxLine(`Previous: ${formatPowerStatus(currentStatus.powerStatus)}`);
@@ -573,11 +726,48 @@ export class NupstDaemon {
         // Update the status in the map
         this.upsStatus.set(ups.id, updatedStatus);
       } catch (error) {
+        // Network loss / query failure tracking
+        const currentStatus = this.upsStatus.get(ups.id);
+        const failures = Math.min(
+          (currentStatus?.consecutiveFailures || 0) + 1,
+          NETWORK.MAX_CONSECUTIVE_FAILURES,
+        );
+
         logger.error(
-          `Error checking UPS ${ups.name} (${ups.id}): ${
+          `Error checking UPS ${ups.name} (${ups.id}) [failure ${failures}/${NETWORK.CONSECUTIVE_FAILURE_THRESHOLD}]: ${
             error instanceof Error ? error.message : String(error)
           }`,
         );
+
+        // Transition to unreachable after threshold consecutive failures
+        if (
+          failures >= NETWORK.CONSECUTIVE_FAILURE_THRESHOLD &&
+          currentStatus &&
+          currentStatus.powerStatus !== 'unreachable'
+        ) {
+          const currentTime = Date.now();
+          const previousStatus = { ...currentStatus };
+
+          currentStatus.powerStatus = 'unreachable';
+          currentStatus.consecutiveFailures = failures;
+          currentStatus.unreachableSince = currentTime;
+          currentStatus.lastStatusChange = currentTime;
+          this.upsStatus.set(ups.id, currentStatus);
+
+          logger.log('');
+          logger.logBoxTitle(`UPS Unreachable: ${ups.name}`, 60, 'error');
+          logger.logBoxLine(`${failures} consecutive communication failures`);
+          logger.logBoxLine(`Last known status: ${formatPowerStatus(previousStatus.powerStatus)}`);
+          logger.logBoxLine(`Time: ${new Date().toISOString()}`);
+          logger.logBoxEnd();
+          logger.log('');
+
+          // Trigger power status change action for unreachable
+          await this.triggerUpsActions(ups, currentStatus, previousStatus, 'powerStatusChange');
+        } else if (currentStatus) {
+          currentStatus.consecutiveFailures = failures;
+          this.upsStatus.set(ups.id, currentStatus);
+        }
       }
     }
   }
@@ -589,8 +779,16 @@ export class NupstDaemon {
     const timestamp = new Date().toISOString();
 
     logger.log('');
-    logger.logBoxTitle('Periodic Status Update', 70, 'info');
+    const pauseLabel = this.isPaused ? ' [PAUSED]' : '';
+    logger.logBoxTitle(`Periodic Status Update${pauseLabel}`, 70, this.isPaused ? 'warning' : 'info');
     logger.logBoxLine(`Timestamp: ${timestamp}`);
+    if (this.isPaused && this.pauseState) {
+      logger.logBoxLine(`Actions paused by: ${this.pauseState.pausedBy}`);
+      if (this.pauseState.resumeAt) {
+        const remaining = Math.round((this.pauseState.resumeAt - Date.now()) / 1000);
+        logger.logBoxLine(`Auto-resume in: ${remaining > 0 ? remaining : 0} seconds`);
+      }
+    }
     logger.logBoxEnd();
     logger.log('');
 
@@ -660,6 +858,14 @@ export class NupstDaemon {
     previousStatus: IUpsStatus | undefined,
     triggerReason: 'powerStatusChange' | 'thresholdViolation',
   ): Promise<void> {
+    // Check if actions are paused
+    if (this.isPaused) {
+      logger.info(
+        `[PAUSED] Actions suppressed for UPS ${ups.name} (trigger: ${triggerReason})`,
+      );
+      return;
+    }
+
     const actions = ups.actions || [];
 
     // Backward compatibility: if no actions configured, use default shutdown behavior
@@ -836,7 +1042,10 @@ export class NupstDaemon {
         // Check all UPS devices
         for (const ups of this.config.upsDevices) {
           try {
-            const status = await this.snmp.getUpsStatus(ups.snmp);
+            const protocol = ups.protocol || 'snmp';
+            const status = protocol === 'upsd' && ups.upsd
+              ? await this.protocolResolver.getUpsStatus('upsd', undefined, ups.upsd)
+              : await this.protocolResolver.getUpsStatus('snmp', ups.snmp);
 
             const batteryColor = getBatteryColor(status.batteryCapacity);
             const runtimeColor = getRuntimeColor(status.batteryRuntime);
@@ -1065,7 +1274,7 @@ export class NupstDaemon {
           logger.log('Config file watcher started');
 
           for await (const event of watcher) {
-            // Only respond to modify events on the config file
+            // Respond to modify events on config file
             if (
               event.kind === 'modify' &&
               event.paths.some((p) => p.includes('config.json'))
@@ -1074,6 +1283,14 @@ export class NupstDaemon {
               await this.reloadConfig();
             }
 
+            // Detect pause file changes
+            if (
+              (event.kind === 'create' || event.kind === 'modify' || event.kind === 'remove') &&
+              event.paths.some((p) => p.includes('pause'))
+            ) {
+              this.checkPauseState();
+            }
+
             // Stop watching if daemon stopped
             if (!this.isRunning) {
               break;

ts/http-server.ts

@@ -1,7 +1,7 @@
 import * as http from 'node:http';
 import { URL } from 'node:url';
 import { logger } from './logger.ts';
-import type { IUpsStatus } from './daemon.ts';
+import type { IPauseState, IUpsStatus } from './daemon.ts';
 
 /**
  * HTTP Server for exposing UPS status as JSON
@@ -13,6 +13,7 @@ export class NupstHttpServer {
   private path: string;
   private authToken: string;
   private getUpsStatus: () => Map<string, IUpsStatus>;
+  private getPauseState: () => IPauseState | null;
 
   /**
    * Create a new HTTP server instance
@@ -20,17 +21,20 @@ export class NupstHttpServer {
    * @param path URL path for the endpoint
    * @param authToken Authentication token required for access
    * @param getUpsStatus Function to retrieve cached UPS status
+   * @param getPauseState Function to retrieve current pause state
    */
   constructor(
     port: number,
     path: string,
     authToken: string,
     getUpsStatus: () => Map<string, IUpsStatus>,
+    getPauseState: () => IPauseState | null,
   ) {
     this.port = port;
     this.path = path;
     this.authToken = authToken;
     this.getUpsStatus = getUpsStatus;
+    this.getPauseState = getPauseState;
   }
 
   /**
@@ -79,12 +83,18 @@ export class NupstHttpServer {
         // Get cached status (no refresh)
         const statusMap = this.getUpsStatus();
         const statusArray = Array.from(statusMap.values());
+        const pauseState = this.getPauseState();
+
+        const response = {
+          upsDevices: statusArray,
+          ...(pauseState ? { paused: true, pauseState } : { paused: false }),
+        };
 
         res.writeHead(200, {
           'Content-Type': 'application/json',
           'Cache-Control': 'no-cache',
         });
-        res.end(JSON.stringify(statusArray, null, 2));
+        res.end(JSON.stringify(response, null, 2));
       } else {
         res.writeHead(404, { 'Content-Type': 'application/json' });
         res.end(JSON.stringify({ error: 'Not Found' }));

ts/migrations/index.ts

@@ -9,3 +9,4 @@ export { MigrationRunner } from './migration-runner.ts';
 export { MigrationV1ToV2 } from './migration-v1-to-v2.ts';
 export { MigrationV3ToV4 } from './migration-v3-to-v4.ts';
 export { MigrationV4_0ToV4_1 } from './migration-v4.0-to-v4.1.ts';
+export { MigrationV4_1ToV4_2 } from './migration-v4.1-to-v4.2.ts';

ts/migrations/migration-runner.ts

@@ -2,6 +2,7 @@ import { BaseMigration } from './base-migration.ts';
 import { MigrationV1ToV2 } from './migration-v1-to-v2.ts';
 import { MigrationV3ToV4 } from './migration-v3-to-v4.ts';
 import { MigrationV4_0ToV4_1 } from './migration-v4.0-to-v4.1.ts';
+import { MigrationV4_1ToV4_2 } from './migration-v4.1-to-v4.2.ts';
 import { logger } from '../logger.ts';
 
 /**
@@ -19,7 +20,7 @@ export class MigrationRunner {
       new MigrationV1ToV2(),
       new MigrationV3ToV4(),
       new MigrationV4_0ToV4_1(),
-      // Add future migrations here (v4.3, v4.4, etc.)
+      new MigrationV4_1ToV4_2(),
     ];
 
     // Sort by version order to ensure they run in sequence

ts/migrations/migration-v4.1-to-v4.2.ts

@@ -0,0 +1,43 @@
+import { BaseMigration } from './base-migration.ts';
+import { logger } from '../logger.ts';
+
+/**
+ * Migration from v4.1 to v4.2
+ *
+ * Changes:
+ * 1. Adds `protocol: 'snmp'` to all existing UPS devices (explicit default)
+ * 2. Bumps version from '4.1' to '4.2'
+ */
+export class MigrationV4_1ToV4_2 extends BaseMigration {
+  readonly fromVersion = '4.1';
+  readonly toVersion = '4.2';
+
+  shouldRun(config: Record<string, unknown>): boolean {
+    return config.version === '4.1';
+  }
+
+  migrate(config: Record<string, unknown>): Record<string, unknown> {
+    logger.info(`${this.getName()}: Adding protocol field to UPS devices...`);
+
+    const devices = (config.upsDevices as Array<Record<string, unknown>>) || [];
+    const migratedDevices = devices.map((device) => {
+      // Add protocol: 'snmp' if not already present
+      if (!device.protocol) {
+        device.protocol = 'snmp';
+        logger.dim(`    → ${device.name}: Set protocol to 'snmp'`);
+      }
+      return device;
+    });
+
+    const result = {
+      ...config,
+      version: this.toVersion,
+      upsDevices: migratedDevices,
+    };
+
+    logger.success(
+      `${this.getName()}: Migration complete (${migratedDevices.length} devices updated)`,
+    );
+    return result;
+  }
+}

ts/nupst.ts

@@ -1,4 +1,5 @@
 import { NupstSnmp } from './snmp/manager.ts';
+import { NupstUpsd } from './upsd/client.ts';
 import { NupstDaemon } from './daemon.ts';
 import { NupstSystemd } from './systemd.ts';
 import denoConfig from '../deno.json' with { type: 'json' };
@@ -17,6 +18,7 @@ import type { INupstAccessor, IUpdateStatus } from './interfaces/index.ts';
  */
 export class Nupst implements INupstAccessor {
   private readonly snmp: NupstSnmp;
+  private readonly upsd: NupstUpsd;
   private readonly daemon: NupstDaemon;
   private readonly systemd: NupstSystemd;
   private readonly upsHandler: UpsHandler;
@@ -34,7 +36,8 @@ export class Nupst implements INupstAccessor {
     // Initialize core components
     this.snmp = new NupstSnmp();
     this.snmp.setNupst(this); // Set up bidirectional reference
-    this.daemon = new NupstDaemon(this.snmp);
+    this.upsd = new NupstUpsd();
+    this.daemon = new NupstDaemon(this.snmp, this.upsd);
     this.systemd = new NupstSystemd(this.daemon);
 
     // Initialize handlers
@@ -52,6 +55,13 @@ export class Nupst implements INupstAccessor {
     return this.snmp;
   }
 
+  /**
+   * Get the UPSD manager for NUT protocol communication
+   */
+  public getUpsd(): NupstUpsd {
+    return this.upsd;
+  }
+
   /**
    * Get the daemon manager for background monitoring
    */

ts/protocol/index.ts

@@ -0,0 +1,7 @@
+/**
+ * Protocol abstraction module
+ * Re-exports public types and classes
+ */
+
+export type { TProtocol } from './types.ts';
+export { ProtocolResolver } from './resolver.ts';

ts/protocol/resolver.ts

@@ -0,0 +1,49 @@
+/**
+ * ProtocolResolver - Routes UPS status queries to the correct protocol implementation
+ *
+ * Abstracts away SNMP vs UPSD differences so the daemon is protocol-agnostic.
+ * Both protocols return the same IUpsStatus interface from ts/snmp/types.ts.
+ */
+
+import type { NupstSnmp } from '../snmp/manager.ts';
+import type { NupstUpsd } from '../upsd/client.ts';
+import type { ISnmpConfig, IUpsStatus } from '../snmp/types.ts';
+import type { IUpsdConfig } from '../upsd/types.ts';
+import type { TProtocol } from './types.ts';
+
+export class ProtocolResolver {
+  private snmp: NupstSnmp;
+  private upsd: NupstUpsd;
+
+  constructor(snmp: NupstSnmp, upsd: NupstUpsd) {
+    this.snmp = snmp;
+    this.upsd = upsd;
+  }
+
+  /**
+   * Get UPS status using the specified protocol
+   * @param protocol Protocol to use ('snmp' or 'upsd')
+   * @param snmpConfig SNMP configuration (required for 'snmp' protocol)
+   * @param upsdConfig UPSD configuration (required for 'upsd' protocol)
+   * @returns UPS status
+   */
+  public getUpsStatus(
+    protocol: TProtocol,
+    snmpConfig?: ISnmpConfig,
+    upsdConfig?: IUpsdConfig,
+  ): Promise<IUpsStatus> {
+    switch (protocol) {
+      case 'upsd':
+        if (!upsdConfig) {
+          throw new Error('UPSD configuration required for UPSD protocol');
+        }
+        return this.upsd.getUpsStatus(upsdConfig);
+      case 'snmp':
+      default:
+        if (!snmpConfig) {
+          throw new Error('SNMP configuration required for SNMP protocol');
+        }
+        return this.snmp.getUpsStatus(snmpConfig);
+    }
+  }
+}

ts/protocol/types.ts

@@ -0,0 +1,4 @@
+/**
+ * Protocol type for UPS communication
+ */
+export type TProtocol = 'snmp' | 'upsd';

ts/snmp/types.ts

@@ -9,7 +9,7 @@ import { Buffer } from 'node:buffer';
  */
 export interface IUpsStatus {
   /** Current power status */
-  powerStatus: 'online' | 'onBattery' | 'unknown';
+  powerStatus: 'online' | 'onBattery' | 'unknown' | 'unreachable';
   /** Battery capacity percentage */
   batteryCapacity: number;
   /** Remaining runtime in minutes */

ts/systemd.ts

@@ -346,13 +346,24 @@ WantedBy=multi-user.target
    */
   private async displaySingleUpsStatus(ups: IUpsConfig, snmp: NupstSnmp): Promise<void> {
     try {
-      // Create a test config with a short timeout
+      const protocol = ups.protocol || 'snmp';
-      const testConfig = {
+      let status;
-        ...ups.snmp,
-        timeout: Math.min(ups.snmp.timeout, 10000), // Use at most 10 seconds for status check
-      };
 
-      const status = await snmp.getUpsStatus(testConfig);
+      if (protocol === 'upsd' && ups.upsd) {
+        const testConfig = {
+          ...ups.upsd,
+          timeout: Math.min(ups.upsd.timeout, 10000),
+        };
+        status = await this.daemon.getNupstUpsd().getUpsStatus(testConfig);
+      } else if (ups.snmp) {
+        const testConfig = {
+          ...ups.snmp,
+          timeout: Math.min(ups.snmp.timeout, 10000),
+        };
+        status = await snmp.getUpsStatus(testConfig);
+      } else {
+        throw new Error('No protocol configuration found');
+      }
 
       // Determine status symbol based on power status
       let statusSymbol = symbols.unknown;
@@ -396,7 +407,12 @@ WantedBy=multi-user.target
       );
 
       // Display host info
-      logger.log(`    ${theme.dim(`Host: ${ups.snmp.host}:${ups.snmp.port}`)}`);
+      const hostInfo = protocol === 'upsd' && ups.upsd
+        ? `${ups.upsd.host}:${ups.upsd.port} (UPSD)`
+        : ups.snmp
+        ? `${ups.snmp.host}:${ups.snmp.port} (SNMP)`
+        : 'N/A';
+      logger.log(`    ${theme.dim(`Host: ${hostInfo}`)}`);
 
       // Display groups if any
       if (ups.groups && ups.groups.length > 0) {
@@ -434,11 +450,16 @@ WantedBy=multi-user.target
       logger.log('');
     } catch (error) {
       // Display error for this UPS
+      const errorHostInfo = (ups.protocol || 'snmp') === 'upsd' && ups.upsd
+        ? `${ups.upsd.host}:${ups.upsd.port} (UPSD)`
+        : ups.snmp
+        ? `${ups.snmp.host}:${ups.snmp.port} (SNMP)`
+        : 'N/A';
       logger.log(
         `  ${symbols.error} ${theme.highlight(ups.name)} - ${theme.error('Connection failed')}`,
       );
       logger.log(`    ${theme.dim(error instanceof Error ? error.message : String(error))}`);
-      logger.log(`    ${theme.dim(`Host: ${ups.snmp.host}:${ups.snmp.port}`)}`);
+      logger.log(`    ${theme.dim(`Host: ${errorHostInfo}`)}`);
       logger.log('');
     }
   }

ts/upsd/client.ts

@@ -0,0 +1,269 @@
+/**
+ * UPSD/NIS (Network UPS Tools) TCP client
+ *
+ * Connects to a NUT upsd server via TCP and queries UPS variables
+ * using the NUT network protocol (RFC-style line protocol).
+ *
+ * Protocol format:
+ *   Request:  GET VAR <upsname> <varname>\n
+ *   Response: VAR <upsname> <varname> "<value>"\n
+ *   Logout:   LOGOUT\n
+ */
+
+import * as net from 'node:net';
+import { logger } from '../logger.ts';
+import { UPSD } from '../constants.ts';
+import type { IUpsdConfig } from './types.ts';
+import type { IUpsStatus } from '../snmp/types.ts';
+
+/**
+ * NupstUpsd - TCP client for the NUT UPSD protocol
+ */
+export class NupstUpsd {
+  private debug = false;
+
+  /**
+   * Enable debug logging
+   */
+  public enableDebug(): void {
+    this.debug = true;
+    logger.info('UPSD debug mode enabled');
+  }
+
+  /**
+   * Get the current UPS status via UPSD protocol
+   * @param config UPSD connection configuration
+   * @returns UPS status matching the IUpsStatus interface
+   */
+  public async getUpsStatus(config: IUpsdConfig): Promise<IUpsStatus> {
+    const host = config.host || '127.0.0.1';
+    const port = config.port || UPSD.DEFAULT_PORT;
+    const upsName = config.upsName || UPSD.DEFAULT_UPS_NAME;
+    const timeout = config.timeout || UPSD.DEFAULT_TIMEOUT_MS;
+
+    if (this.debug) {
+      logger.dim('---------------------------------------');
+      logger.dim('Getting UPS status via UPSD protocol:');
+      logger.dim(`  Host: ${host}:${port}`);
+      logger.dim(`  UPS Name: ${upsName}`);
+      logger.dim(`  Timeout: ${timeout}ms`);
+      logger.dim('---------------------------------------');
+    }
+
+    // Variables to query from NUT
+    const varsToQuery = [
+      'ups.status',
+      'battery.charge',
+      'battery.runtime',
+      'ups.load',
+      'ups.realpower',
+      'output.voltage',
+      'output.current',
+    ];
+
+    const values = new Map<string, string>();
+
+    // Open a TCP connection, query all variables, then logout
+    const conn = await this.connect(host, port, timeout);
+
+    try {
+      // Authenticate if credentials provided
+      if (config.username && config.password) {
+        await this.sendCommand(conn, `USERNAME ${config.username}`, timeout);
+        await this.sendCommand(conn, `PASSWORD ${config.password}`, timeout);
+      }
+
+      // Query each variable
+      for (const varName of varsToQuery) {
+        const value = await this.safeGetVar(conn, upsName, varName, timeout);
+        if (value !== null) {
+          values.set(varName, value);
+        }
+      }
+
+      // Logout gracefully
+      try {
+        await this.sendCommand(conn, 'LOGOUT', timeout);
+      } catch (_e) {
+        // Ignore logout errors
+      }
+    } finally {
+      conn.destroy();
+    }
+
+    // Map NUT variables to IUpsStatus
+    const powerStatus = this.parsePowerStatus(values.get('ups.status') || '');
+    const batteryCapacity = parseFloat(values.get('battery.charge') || '0');
+    const batteryRuntimeSeconds = parseFloat(values.get('battery.runtime') || '0');
+    const batteryRuntime = Math.floor(batteryRuntimeSeconds / 60); // NUT reports seconds, convert to minutes
+    const outputLoad = parseFloat(values.get('ups.load') || '0');
+    const outputPower = parseFloat(values.get('ups.realpower') || '0');
+    const outputVoltage = parseFloat(values.get('output.voltage') || '0');
+    const outputCurrent = parseFloat(values.get('output.current') || '0');
+
+    const result: IUpsStatus = {
+      powerStatus,
+      batteryCapacity: isNaN(batteryCapacity) ? 0 : batteryCapacity,
+      batteryRuntime: isNaN(batteryRuntime) ? 0 : batteryRuntime,
+      outputLoad: isNaN(outputLoad) ? 0 : outputLoad,
+      outputPower: isNaN(outputPower) ? 0 : outputPower,
+      outputVoltage: isNaN(outputVoltage) ? 0 : outputVoltage,
+      outputCurrent: isNaN(outputCurrent) ? 0 : outputCurrent,
+      raw: Object.fromEntries(values),
+    };
+
+    if (this.debug) {
+      logger.dim('---------------------------------------');
+      logger.dim('UPSD status result:');
+      logger.dim(`  Power Status: ${result.powerStatus}`);
+      logger.dim(`  Battery Capacity: ${result.batteryCapacity}%`);
+      logger.dim(`  Battery Runtime: ${result.batteryRuntime} minutes`);
+      logger.dim(`  Output Load: ${result.outputLoad}%`);
+      logger.dim(`  Output Power: ${result.outputPower} watts`);
+      logger.dim(`  Output Voltage: ${result.outputVoltage} volts`);
+      logger.dim(`  Output Current: ${result.outputCurrent} amps`);
+      logger.dim('---------------------------------------');
+    }
+
+    return result;
+  }
+
+  /**
+   * Open a TCP connection to the UPSD server
+   */
+  private connect(host: string, port: number, timeout: number): Promise<net.Socket> {
+    return new Promise((resolve, reject) => {
+      const socket = net.createConnection({ host, port }, () => {
+        if (this.debug) {
+          logger.dim(`Connected to UPSD at ${host}:${port}`);
+        }
+        resolve(socket);
+      });
+
+      socket.setTimeout(timeout);
+      socket.on('timeout', () => {
+        socket.destroy();
+        reject(new Error(`UPSD connection timed out after ${timeout}ms`));
+      });
+      socket.on('error', (err) => {
+        reject(new Error(`UPSD connection error: ${err.message}`));
+      });
+    });
+  }
+
+  /**
+   * Send a command and read the response line
+   */
+  private sendCommand(socket: net.Socket, command: string, timeout: number): Promise<string> {
+    return new Promise((resolve, reject) => {
+      let responseData = '';
+      const timer = setTimeout(() => {
+        cleanup();
+        reject(new Error(`UPSD command timed out: ${command}`));
+      }, timeout);
+
+      const decoder = new TextDecoder();
+      const onData = (data: Uint8Array) => {
+        responseData += decoder.decode(data, { stream: true });
+        // Look for newline to indicate end of response
+        const newlineIdx = responseData.indexOf('\n');
+        if (newlineIdx !== -1) {
+          cleanup();
+          const line = responseData.substring(0, newlineIdx).trim();
+          if (this.debug) {
+            logger.dim(`UPSD << ${line}`);
+          }
+          resolve(line);
+        }
+      };
+
+      const onError = (err: Error) => {
+        cleanup();
+        reject(err);
+      };
+
+      const cleanup = () => {
+        clearTimeout(timer);
+        socket.removeListener('data', onData);
+        socket.removeListener('error', onError);
+      };
+
+      socket.on('data', onData);
+      socket.on('error', onError);
+
+      if (this.debug) {
+        logger.dim(`UPSD >> ${command}`);
+      }
+      socket.write(command + '\n');
+    });
+  }
+
+  /**
+   * Safely get a single NUT variable, returning null on error
+   */
+  private async safeGetVar(
+    socket: net.Socket,
+    upsName: string,
+    varName: string,
+    timeout: number,
+  ): Promise<string | null> {
+    try {
+      const response = await this.sendCommand(
+        socket,
+        `GET VAR ${upsName} ${varName}`,
+        timeout,
+      );
+
+      // Expected response: VAR <upsname> <varname> "<value>"
+      // Also handle: ERR ... for unsupported variables
+      if (response.startsWith('ERR')) {
+        if (this.debug) {
+          logger.dim(`UPSD variable ${varName} not available: ${response}`);
+        }
+        return null;
+      }
+
+      // Parse: VAR ups battery.charge "100"
+      const match = response.match(/^VAR\s+\S+\s+\S+\s+"(.*)"/);
+      if (match) {
+        return match[1];
+      }
+
+      // Some implementations don't quote the value
+      const parts = response.split(/\s+/);
+      if (parts.length >= 4 && parts[0] === 'VAR') {
+        return parts.slice(3).join(' ').replace(/^"/, '').replace(/"$/, '');
+      }
+
+      if (this.debug) {
+        logger.dim(`UPSD unexpected response for ${varName}: ${response}`);
+      }
+      return null;
+    } catch (error) {
+      if (this.debug) {
+        logger.dim(
+          `UPSD error getting ${varName}: ${error instanceof Error ? error.message : String(error)}`,
+        );
+      }
+      return null;
+    }
+  }
+
+  /**
+   * Parse NUT ups.status tokens into a power status
+   * NUT status tokens: OL (online), OB (on battery), LB (low battery),
+   * HB (high battery), RB (replace battery), CHRG (charging), etc.
+   */
+  private parsePowerStatus(statusString: string): 'online' | 'onBattery' | 'unknown' {
+    const tokens = statusString.trim().split(/\s+/);
+
+    if (tokens.includes('OB')) {
+      return 'onBattery';
+    }
+    if (tokens.includes('OL')) {
+      return 'online';
+    }
+
+    return 'unknown';
+  }
+}

ts/upsd/index.ts

@@ -0,0 +1,7 @@
+/**
+ * UPSD/NIS protocol module
+ * Re-exports public types and classes
+ */
+
+export type { IUpsdConfig } from './types.ts';
+export { NupstUpsd } from './client.ts';

ts/upsd/types.ts

@@ -0,0 +1,21 @@
+/**
+ * Type definitions for UPSD/NIS (Network UPS Tools) protocol module
+ */
+
+/**
+ * UPSD connection configuration
+ */
+export interface IUpsdConfig {
+  /** UPSD server host (default: 127.0.0.1) */
+  host: string;
+  /** UPSD server port (default: 3493) */
+  port: number;
+  /** NUT device name (default: 'ups') */
+  upsName: string;
+  /** Connection timeout in milliseconds (default: 5000) */
+  timeout: number;
+  /** Optional username for authentication */
+  username?: string;
+  /** Optional password for authentication */
+  password?: string;
+}