diff --git a/scripts/spt25.gd b/scripts/spt25.gd
index 9a93110..a0bc53a 100644
--- a/scripts/spt25.gd
+++ b/scripts/spt25.gd
@@ -5,6 +5,12 @@ const REQUEST_PERIOD: int = 3000  ## Переиод запроса, мс
 
 class SPT25 extends unit.Unit:
 
+    enum CmdCode {
+        START = 0,
+        STOP  = 2,
+        INFO  = 4,
+        }
+
     func _to_string() -> String: return String('СПТ-25 %s %s' % [self.name, ['отключен', 'на связи'][int(online)]])
 
     func _init(nm) -> void:
@@ -22,12 +28,18 @@ class SPT25 extends unit.Unit:
 
     func parse(rx_data: PackedByteArray, tick: int):
         rx_tick = tick
-        if not online:
-            online = true
-            emit_signal('line_changed', self)
         if rx_data.size() <= 6:
             emit_signal('parse_failed', self)
             return
+        if rx_data[0] != 0x7e:
+            emit_signal('parse_failed', self)
+            return
+        if not (rx_data[2] in [CmdCode.START, CmdCode.STOP, CmdCode.INFO]):
+            emit_signal('parse_failed', self)
+            return
+        if not online:
+            online = true
+            emit_signal('line_changed', self)
         emit_signal('data_received', rx_data)