diff --git a/src/components/ClientMonitor/ClientMonitorPage.tsx b/src/components/ClientMonitor/ClientMonitorPage.tsx
index efba56c..120a510 100644
--- a/src/components/ClientMonitor/ClientMonitorPage.tsx
+++ b/src/components/ClientMonitor/ClientMonitorPage.tsx
@@ -53,7 +53,11 @@ function formatApiDateTime(value: unknown): string {
 import PrinterMonitorTab from "@/components/ClientMonitor/PrinterMonitorTab";
 import LabelPrinterMonitorPanel from "@/components/ClientMonitor/LabelPrinterMonitorPanel";
 import DeviceConnectivityHistoryChart from "@/components/ClientMonitor/DeviceConnectivityHistoryChart";
-import { formatClientIpDisplay } from "@/lib/devicePresence";
+import {
+  extractDeviceUniqueSuffix,
+  formatClientIpDisplay,
+  formatDeviceDisplayLabel,
+} from "@/lib/devicePresence";
 
 type ClientRow = {
   deviceId: string;
@@ -145,7 +149,7 @@ function toApiDateTime(value: Dayjs | null): string {
 }
 
 function defaultHistoryFrom(): Dayjs {
-  return dayjs().startOf("day");
+  return dayjs().subtract(6, "day").startOf("day");
 }
 
 function defaultHistoryTo(): Dayjs {
@@ -176,6 +180,7 @@ export default function ClientMonitorPage() {
     useState<PrinterHistorySummary | null>(null);
   const [historyLoading, setHistoryLoading] = useState(false);
   const [historyError, setHistoryError] = useState<string | null>(null);
+  const [historyQueried, setHistoryQueried] = useState(false);
   const [historyDefinitionsOpen, setHistoryDefinitionsOpen] = useState(false);
   const historyFetchInFlightRef = useRef(false);
 
@@ -297,6 +302,7 @@ export default function ClientMonitorPage() {
         setPrinterHistoryRows([]);
         setPrinterHistorySummary(null);
       }
+      setHistoryQueried(true);
     } catch (e) {
       console.error("client monitor history", e);
       setHistoryError(e instanceof Error ? e.message : "無法載入歷史記錄");
@@ -330,6 +336,13 @@ export default function ClientMonitorPage() {
     return () => window.clearInterval(id);
   }, [fetchClients, tab]);
 
+  useEffect(() => {
+    if (tab !== "history") return;
+    void fetchHistory();
+    // Auto-load when opening the history tab; filter changes use the 查詢 button.
+    // eslint-disable-next-line react-hooks/exhaustive-deps
+  }, [tab]);
+
   const offlineCount = summary?.offline ?? 0;
 
   return (
@@ -391,8 +404,8 @@ export default function ClientMonitorPage() {
       {tab === "live" && (
         <>
           <Typography variant="body2" color="text.secondary">
-            顯示所有已登入並開啟 FPSMS 的瀏覽器（平板、電腦等）。超過約 90 秒無心跳視為離線；超過 5
-            分鐘無頁面活動視為閒置。每 10 秒自動更新。
+            顯示最近 7 天內有心跳的裝置（平板、電腦等）。超過約 90 秒無心跳視為離線；超過 5
+            分鐘無頁面活動視為閒置。長期離線的舊紀錄會自動隱藏並清除。每 10 秒自動更新。
           </Typography>
 
           {offlineCount > 0 && (
@@ -466,11 +479,11 @@ export default function ClientMonitorPage() {
                           <Chip size="small" color={st.color} label={st.label} />
                         </TableCell>
                         <TableCell>
-                          <Typography variant="body2" fontWeight={600}>
-                            {row.displayName || row.deviceId.slice(0, 8) + "…"}
+                          <Typography variant="body2" fontWeight={600} title={row.deviceId}>
+                            {formatDeviceDisplayLabel(row)}
                           </Typography>
-                          <Typography variant="caption" color="text.secondary">
-                            {row.deviceId}
+                          <Typography variant="caption" color="text.secondary" title={row.deviceId}>
+                            #{extractDeviceUniqueSuffix(row.deviceId)}
                           </Typography>
                         </TableCell>
                         <TableCell>
@@ -532,7 +545,8 @@ export default function ClientMonitorPage() {
         <>
           <Typography variant="body2" color="text.secondary" sx={{ mb: 1 }}>
             查詢指定時間範圍內的<strong>裝置</strong>（平板／電腦）與<strong>印表機</strong>異常記錄（最長
-            30 天）。圖表與表格分開顯示；超過 30 天的記錄會由系統自動清除。
+            30 天）。僅記錄<strong>離線</strong>與<strong>連線差</strong>事件；在線或閒置不會出現在此。切換到此分頁會自動查詢最近
+            7 天。
           </Typography>
 
           <Button
@@ -696,6 +710,7 @@ export default function ClientMonitorPage() {
                 events={historyRows}
                 fromLocal={historyFrom.format("YYYY-MM-DDTHH:mm:ss")}
                 toLocal={historyTo.format("YYYY-MM-DDTHH:mm:ss")}
+                queried={historyQueried && !historyLoading}
               />
             </>
           )}
@@ -740,11 +755,11 @@ export default function ClientMonitorPage() {
                           <Chip size="small" color={st.color} label={st.label} />
                         </TableCell>
                         <TableCell>
-                          <Typography variant="body2" fontWeight={600}>
-                            {row.displayName || row.deviceId.slice(0, 8) + "…"}
+                          <Typography variant="body2" fontWeight={600} title={row.deviceId}>
+                            {formatDeviceDisplayLabel(row)}
                           </Typography>
-                          <Typography variant="caption" color="text.secondary">
-                            {row.deviceId}
+                          <Typography variant="caption" color="text.secondary" title={row.deviceId}>
+                            #{extractDeviceUniqueSuffix(row.deviceId)}
                           </Typography>
                         </TableCell>
                         <TableCell>
@@ -782,6 +797,7 @@ export default function ClientMonitorPage() {
                 toLocal={historyTo.format("YYYY-MM-DDTHH:mm:ss")}
                 title="印表機離線狀況圖"
                 variant="printer"
+                queried={historyQueried && !historyLoading}
               />
               <TableContainer className="rounded-lg border border-slate-200 bg-white dark:border-slate-700 dark:bg-slate-800">
                 <Table size="small">
diff --git a/src/components/ClientMonitor/DeviceConnectivityHistoryChart.tsx b/src/components/ClientMonitor/DeviceConnectivityHistoryChart.tsx
index 576fbb4..87e27c6 100644
--- a/src/components/ClientMonitor/DeviceConnectivityHistoryChart.tsx
+++ b/src/components/ClientMonitor/DeviceConnectivityHistoryChart.tsx
@@ -1,7 +1,7 @@
 "use client";
 
 import React, { useMemo } from "react";
-import { Box, Typography } from "@mui/material";
+import { Alert, Box, Typography } from "@mui/material";
 import type { ApexOptions } from "apexcharts";
 import SafeApexCharts from "@/components/charts/SafeApexCharts";
 import {
@@ -17,6 +17,8 @@ type Props = {
   subtitle?: string;
   /** printer: only offline events; area chart label for distinct printers */
   variant?: "device" | "printer";
+  /** When false, prompt user to run a query first. */
+  queried?: boolean;
 };
 
 export default function DeviceConnectivityHistoryChart({
@@ -26,6 +28,7 @@ export default function DeviceConnectivityHistoryChart({
   title = "連線狀況圖",
   subtitle,
   variant = "device",
+  queried = true,
 }: Props) {
   const buckets = useMemo(
     () => buildConnectivityChartBuckets(events, fromLocal, toLocal),
@@ -143,21 +146,31 @@ export default function DeviceConnectivityHistoryChart({
       ? "每段時間內印表機 TCP 連線失敗次數（約每 2 分鐘掃描一次）。"
       : "每段時間內離線／連線差事件次數。柱狀愈低愈好；藍線為該時段有異常的裝置數。";
 
+  if (!queried) {
+    return (
+      <Typography color="text.secondary" sx={{ py: 2 }}>
+        選擇時間範圍後按「查詢」，或切換到此分頁時會自動載入。
+      </Typography>
+    );
+  }
+
   if (!buckets || buckets.categories.length === 0) {
     return (
       <Typography color="text.secondary" sx={{ py: 2 }}>
-        選擇時間範圍並查詢後，將顯示連線狀況圖表。
+        無法建立圖表：請確認開始時間早於結束時間。
       </Typography>
     );
   }
 
   const totalOffline = buckets.offlineCounts.reduce((a, b) => a + b, 0);
   const totalPoor = buckets.poorCounts.reduce((a, b) => a + b, 0);
+  const totalEvents = totalOffline + totalPoor;
   const maxAffected = Math.max(...buckets.affectedDeviceCounts, 0);
   const quietBuckets = buckets.affectedDeviceCounts.filter((n) => n === 0).length;
   const healthPct = Math.round(
     (quietBuckets / buckets.affectedDeviceCounts.length) * 100
   );
+  const noIncidents = totalEvents === 0;
 
   return (
     <Box className="space-y-4 rounded-lg border border-slate-200 bg-white p-4 dark:border-slate-700 dark:bg-slate-800">
@@ -173,18 +186,35 @@ export default function DeviceConnectivityHistoryChart({
         <Typography
           variant="h6"
           fontWeight={700}
-          color={healthPct >= 80 ? "success.main" : healthPct >= 50 ? "warning.main" : "error.main"}
+          color={
+            noIncidents
+              ? "success.main"
+              : healthPct >= 80
+                ? "success.main"
+                : healthPct >= 50
+                  ? "warning.main"
+                  : "error.main"
+          }
         >
-          穩定時段 {healthPct}%
+          {noIncidents ? "此區間無異常" : `穩定時段 ${healthPct}%`}
         </Typography>
       </Box>
 
+      {noIncidents && (
+        <Alert severity="success" sx={{ py: 0.5 }}>
+          {variant === "printer"
+            ? "此時間範圍內沒有印表機離線記錄。"
+            : "此時間範圍內沒有裝置離線或連線差記錄（閒置／在線不會寫入歷史）。"}
+        </Alert>
+      )}
+
       <SafeApexCharts
         type="bar"
         height={280}
         series={barSeries}
         options={options}
         chartRevision={`bar-${chartRevision}-${variant}`}
+        allowZeroSeries
       />
 
       <SafeApexCharts
@@ -193,6 +223,7 @@ export default function DeviceConnectivityHistoryChart({
         series={[{ name: "異常裝置數", data: buckets.affectedDeviceCounts }]}
         options={lineOptions}
         chartRevision={`area-${chartRevision}-${variant}`}
+        allowZeroSeries
       />
 
       <Typography variant="caption" color="text.secondary">
diff --git a/src/components/charts/SafeApexCharts.tsx b/src/components/charts/SafeApexCharts.tsx
index cacf369..9b29f4b 100644
--- a/src/components/charts/SafeApexCharts.tsx
+++ b/src/components/charts/SafeApexCharts.tsx
@@ -9,6 +9,8 @@ import type { Props as ApexChartProps } from "react-apexcharts";
 export type SafeApexChartsProps = ApexChartProps & {
   /** Bumps internal remount when set — JSON.stringify(options) drops `chart.events`, so use this when handlers/data must stay in sync. */
   chartRevision?: string | number;
+  /** When true, bar/area charts with all-zero values still render (e.g. connectivity history with no incidents). */
+  allowZeroSeries?: boolean;
 };
 
 /**
@@ -102,6 +104,7 @@ function shouldShowPlaceholder(
   type: ApexChartProps["type"],
   options: ApexChartProps["options"],
   sanitized: ApexChartProps["series"],
+  allowZeroSeries: boolean,
 ): boolean {
   if (!Array.isArray(sanitized) || sanitized.length === 0) return true;
 
@@ -120,7 +123,7 @@ function shouldShowPlaceholder(
   const rows = sanitized as { data?: number[] }[];
   const anyPoint = rows.some((r) => (r.data?.length ?? 0) > 0);
   if (!anyPoint) return true;
-  if (type === "bar" && seriesNumericTotal(sanitized) <= 0) return true;
+  if (!allowZeroSeries && type === "bar" && seriesNumericTotal(sanitized) <= 0) return true;
   return false;
 }
 
@@ -148,7 +151,7 @@ function buildApexConfig(
 const EMPTY_MESSAGE = "暫無圖表資料（後端無法連線或此區間無資料）。";
 
 export default function SafeApexCharts(props: SafeApexChartsProps) {
-  const { type, series, options, height, width, chartRevision, ...rest } = props;
+  const { type, series, options, height, width, chartRevision, allowZeroSeries = false, ...rest } = props;
   const containerRef = useRef<HTMLDivElement>(null);
   const chartRef = useRef<{ destroy: () => void } | null>(null);
 
@@ -159,7 +162,7 @@ export default function SafeApexCharts(props: SafeApexChartsProps) {
     sanitized = alignSeriesToCategoryCount(sanitized, cats.length);
   }
 
-  if (shouldShowPlaceholder(type, options, sanitized)) {
+  if (shouldShowPlaceholder(type, options, sanitized, allowZeroSeries)) {
     return (
       <Typography color="text.secondary" sx={{ py: 3 }}>
         {EMPTY_MESSAGE}
diff --git a/src/lib/devicePresence.ts b/src/lib/devicePresence.ts
index cf551fb..2ce59b1 100644
--- a/src/lib/devicePresence.ts
+++ b/src/lib/devicePresence.ts
@@ -48,6 +48,64 @@ function screenShortSidePx(): number {
  * Classify device for presence monitoring.
  * iPadOS 13+ often sends a desktop Macintosh UA; use touch + platform heuristics.
  */
+export const CLIENT_TYPE_LABEL_ZH: Record<string, string> = {
+  tablet: "平板",
+  desktop: "電腦",
+  mobile: "手機",
+  unknown: "未知",
+};
+
+/** Unique suffix from auto-generated device IDs (e.g. dev-1779250265738-4a07c079 → 4a07c079). */
+export function extractDeviceUniqueSuffix(deviceId: string): string {
+  const trimmed = deviceId.trim();
+  if (!trimmed) return "—";
+  const lastDash = trimmed.lastIndexOf("-");
+  if (lastDash >= 0 && lastDash < trimmed.length - 1) {
+    return trimmed.slice(lastDash + 1);
+  }
+  return trimmed.length > 8 ? trimmed.slice(-8) : trimmed;
+}
+
+/** Last IPv4 octet or full display IP for monitor labels. */
+export function formatDeviceIpShort(ip?: string | null): string | null {
+  if (!ip?.trim()) return null;
+  const display = formatClientIpDisplay(ip);
+  if (display === "—") return null;
+  if (display === "Server") return "Server";
+  const match = display.match(/(\d{1,3})$/);
+  return match ? match[1] : display;
+}
+
+export type DeviceLabelInput = {
+  deviceId: string;
+  displayName?: string | null;
+  username?: string | null;
+  clientIp?: string | null;
+  clientType?: string | null;
+};
+
+/** Human-readable device label for monitor tables when no custom display name is set. */
+export function formatDeviceDisplayLabel(input: DeviceLabelInput): string {
+  const custom = input.displayName?.trim();
+  if (custom) return custom;
+
+  const typeKey = input.clientType?.trim().toLowerCase() ?? "unknown";
+  const typeLabel = CLIENT_TYPE_LABEL_ZH[typeKey] ?? typeKey;
+
+  const username = input.username?.trim();
+  const ipShort = formatDeviceIpShort(input.clientIp);
+
+  const parts: string[] = [typeLabel];
+  if (username) parts.push(username);
+  if (ipShort) parts.push(ipShort);
+
+  if (parts.length > 1) {
+    return parts.join(" · ");
+  }
+
+  return `${typeLabel} · ${extractDeviceUniqueSuffix(input.deviceId)}`;
+}
+
 /** Display IP; loopback / same-machine traffic shows as "Server". */
 export function formatClientIpDisplay(ip?: string | null): string {
   if (!ip?.trim()) return "—";