I want to connect Seatalk on old ST-50 Tridata to new ST-4000 Autopilot. This involves rare adapter cable to go from old round Seatalk to new square plug. Only place I found it was Marine.com, which it turns out is new owners of Sailnet, anyone ordered from them or know another source ? Cable is Raymarine D-188 (round female, preferred) or D-187 (round male) ?