diff --git a/applications/connection_demo/ethernet_demo/ethernet_demo.c b/applications/connection_demo/ethernet_demo/ethernet_demo.c
index ba7c74f3..f0010bc6 100644
--- a/applications/connection_demo/ethernet_demo/ethernet_demo.c
+++ b/applications/connection_demo/ethernet_demo/ethernet_demo.c
@@ -180,6 +180,7 @@ void AtTestCmdEthernet(int argc, char *argv[])
 
     printf("Waiting for msg...\n");
 
+    // Send hfa21 handshake, start cmd mode.
     ATOrderSend(at_adapter->agent, REPLY_TIME_OUT, NULL, "+++");
     UserTaskDelay(100);