diff --git a/src/meshcore/serial_cx.py b/src/meshcore/serial_cx.py
index 8bf9430..172baf4 100644
--- a/src/meshcore/serial_cx.py
+++ b/src/meshcore/serial_cx.py
@@ -16,6 +16,7 @@ class SerialConnection:
         self.frame_size = 0
         self.transport = None
         self.header = b""
+        self.reader = None
         self.inframe = b""
         self._disconnect_callback = None
         self.cx_dly = cx_dly