ICOM OPC-1086 adapter needed to modify/program ICOM marine radios like:
IC-M401Euro, IC-M503, IC-M601

You need an OPC-478 adapter as well to modify/program your radio
with the appropriate ICOM cloning software.
Pls. check your radio's service manual for the 10-pin connector,
the programing pin is at pin 8 and named ICF3 .