In preparation for WPX SSB next weekend I have added a port for a footswitch to the great ICOM RC-28 USB device.
Opening the RC-28 and identifying the pin for the PTT switch.
Adding a wire for external PTT
Drill a 7.5mm hole to add a chinch (RCA) port and solder pin (red) and ground (blue) to the RCA.
Works like a charm!
Remember you are doing this at your own risk and you will lose warrenty.
I am not responsible for any damage or missbehavoir after the tweak!