Uniden 625c VHF's

[My Lady]

I have a nmea connection problem. I recently bought 2 Uniden UM 625c VHF's (perhaps my first mistake) and am trying without success to get my Raymarine GPS 125 to talk to them. I bought them because they spec'd out well and could drive 2 hailer horns. I have not been able to get them to recognize the horns either. Uniden tech support (a joke) said they were probably both defective and to send them in. I said to him "you've got to be kidding, right? Both defective? What does that say for your products? Anyway I'm not willing to sink more $$$ into them and would really appreciate any help I can get to make them work. The tech dude said I had them wired right but couldn't explain. Anyone with any insight before they become boat anchors? Thanks.

[rdempsey]

I had problems getting GPS to work on my 625 as well.
All my other instruments were happy with using ship's electrical ground
for the NMEA "-" connection, but not the 625.
I had to connect "NMEA 0183 IN -" direct to my GPS unit.

Never had a problem with the hailer, it saw it right away.

[MarkSF]

Confusion when making these connections is common, frequently assisted by the manufacturers. When I connected my Lowance GPS to a SH radio, the two support depts. contradicted each other (SH were right, btw)

The problem is often confusion between true double ended inputs/outputs and ones with inverted and non-inverted signals. Both might say NMEA 0183 -, but the connection required is different.

If you can describe how you have it wired, I am willing to bet we can fix it.