diff --git a/pyvlx/api/api_event.py b/pyvlx/api/api_event.py
index c21a36c1..fea21db3 100644
--- a/pyvlx/api/api_event.py
+++ b/pyvlx/api/api_event.py
@@ -28,7 +28,7 @@ async def do_api_call(self) -> None:
         # the semaphore.
         await self.pyvlx.check_connected()
 
-        async with self.pyvlx.sem:
+        async with self.pyvlx.api_call_semaphore:
             self.pyvlx.connection.register_frame_received_cb(self.response_rec_callback)
             await self.send_frame()
             await self.start_timeout()
diff --git a/pyvlx/pyvlx.py b/pyvlx/pyvlx.py
index 1a17b9ae..1625a2c7 100644
--- a/pyvlx/pyvlx.py
+++ b/pyvlx/pyvlx.py
@@ -41,7 +41,7 @@ def __init__(self,
         self.version = None
         self.protocol_version = None
         self.klf200 = Klf200Gateway(pyvlx=self)
-        self.sem = asyncio.Semaphore(1)  # Limit parallel commands
+        self.api_call_semaphore = asyncio.Semaphore(1)  # Limit parallel commands
 
     async def connect(self) -> None:
         """Connect to KLF 200."""