diff --git a/protos/device_state.proto b/protos/device_state.proto
index 8477608..a6d2b70 100644
--- a/protos/device_state.proto
+++ b/protos/device_state.proto
@@ -416,8 +416,10 @@ message TrainMapState{
   uint32 tailDeviceId = 66;
   // 列车车尾所在设备偏移量
   int64 tailOffset = 67;
+  // 列车车尾所在设备端口
+  string tailDevicePort = 68;
   // BTM状态
-  BTMState btmState = 68;
+  BTMState btmState = 69;
 }
 
 message BTMState {