diff --git a/app/src/main/java/com/ouxuan/oxface/debug/Ox485DebugHelper.java b/app/src/main/java/com/ouxuan/oxface/debug/Ox485DebugHelper.java
index 3a84173..92a9a15 100644
--- a/app/src/main/java/com/ouxuan/oxface/debug/Ox485DebugHelper.java
+++ b/app/src/main/java/com/ouxuan/oxface/debug/Ox485DebugHelper.java
@@ -28,7 +28,7 @@ public class Ox485DebugHelper {
         String status = ox485.get485Status();
         LogManager.logInfo(TAG, "当前状态: " + status);
         
-        // 2. 连接诊断
+        // 2. 连接诊断 - 使用Ox485的内部诊断方法
         LogManager.logInfo(TAG, "步骤2: 连接诊断");
         ox485.diagnose485Connection();
         
diff --git a/app/src/main/java/com/ouxuan/oxface/device/Ox485.java b/app/src/main/java/com/ouxuan/oxface/device/Ox485.java
index 6c26ab5..4900f2e 100644
--- a/app/src/main/java/com/ouxuan/oxface/device/Ox485.java
+++ b/app/src/main/java/com/ouxuan/oxface/device/Ox485.java
@@ -182,7 +182,7 @@ public class Ox485 {
      */
     private void sendCommandAndWaitResponse(PeopleNumCallback callback) {
         // 发送前检查串口状态
-        if (!serialPortManager.isOpened()) {
+        if (!isSerialPortReallyOpen()) {
             String errorMsg = "串口未打开，无法发送命令";
             LogManager.logError(TAG, errorMsg);
             isSerialPortOpen = false;
@@ -289,7 +289,7 @@ public class Ox485 {
             long elapsedTime = System.currentTimeMillis() - startTime;
             String errorMsg = "485人数查询超时（等待时间: " + elapsedTime + "ms）";
             LogManager.logError(TAG, errorMsg);
-            LogManager.logError(TAG, "485超时详情 - 串口状态: " + (serialPortManager != null ? serialPortManager.isOpened() : "null") + 
+            LogManager.logError(TAG, "485超时详情 - 串口状态: " + (isSerialPortReallyOpen() ? "已打开" : "未打开") + 
                                    ", 内部连接状态: " + isSerialPortOpen + 
                                    ", 最后成功时间: " + (lastSuccessTime > 0 ? 
                                    new java.text.SimpleDateFormat("HH:mm:ss.SSS").format(new java.util.Date(lastSuccessTime)) : "无"));
@@ -420,7 +420,7 @@ public class Ox485 {
         
         // 2. 检查串口管理器状态
         LogManager.logInfo(TAG, "诊断2 - 串口管理器状态:");
-        LogManager.logInfo(TAG, "  - 串口是否打开: " + (serialPortManager != null ? serialPortManager.isOpened() : "null"));
+        LogManager.logInfo(TAG, "  - 串口是否打开: " + (isSerialPortReallyOpen() ? "已打开" : "未打开"));
         LogManager.logInfo(TAG, "  - 内部连接状态: " + isSerialPortOpen);
         LogManager.logInfo(TAG, "  - 是否连接中: " + isConnecting);
         
@@ -646,7 +646,7 @@ public class Ox485 {
             }
             
             // 验证串口是否真正打开
-            if (!serialPortManager.isOpened()) {
+            if (!isSerialPortReallyOpen()) {
                 isConnecting = false;
                 String errorMsg = "485串口打开后状态检查失败，串口可能未正确初始化";
                 LogManager.logError(TAG, errorMsg);
@@ -747,4 +747,14 @@ public class Ox485 {
         // 15: 0x0F, 3: 0x03, 4: 0x04, 0: 0x00
         return (bytes[0] == 15 && bytes[1] == 3 && bytes[2] == 4 && bytes[3] == 0);
     }
+    
+    /**
+     * 检查串口是否真正打开
+     * 由于 SerialPortManager 没有 isOpened() 方法，
+     * 我们通过检查内部状态变量来判断
+     * @return true表示串口已打开
+     */
+    private boolean isSerialPortReallyOpen() {
+        return isSerialPortOpen && serialPortManager != null;
+    }
 }
\ No newline at end of file