I have a standalone Vesper AIS Watchmate and a standalone Standard Horizon VHF. I am supposed to be able to wire them together so that I don't have to manually enter an MMSI number each time I want to call a ship by DSC on the VHF. I'm finally getting around to wiring them together, but it doesn't seem to work.

The AIS directions say to simply connect the two wires of the AIS output to the corresponding VHF input wires, and change the port setting on the AIS to "NMEA only 4800." I did this, and it didn't work. I then went ahead and connected the two VHF output wires to the corresponding AIS input wires, but still nothing.

I've checked that I've got the correct wires paired up, with a good connection. I've written Vesper, but wonder if anyone here has done this with a Vesper Watchmate or has any suggestions.

Thanks,
Max