Does anybody know how to connect the sounder side of a Garmin
125 GPS/Sounder to the sounder transducer
. The only manual I can find says lots about hooking up the GPS
side, NEMA inputs and outputs, etc. but is silent re the depthsounder transducer
. I know it's an old unit but I've been happily using the GPS
side for years and I'd like to get the sounder side working as a backup to my main unit. Thanks!