diff --git a/tests/simyaesu.c b/tests/simyaesu.c
index 9041575db..015b9ef05 100644
--- a/tests/simyaesu.c
+++ b/tests/simyaesu.c
@@ -1,3 +1,5 @@
+// can run this using rigctl/rigctld and socat pty devices
+// socat -d -d pty,raw,echo=0 pty,raw,echo=0
 #include <stdio.h>
 #include <string.h>
 #include <unistd.h>