NMEA compatibility

[Miker]

I've replaced my Garmin GPS 120XL with a GPS152 and also replaced the old switchboard and labelled the wiring - the wiring was like a mass of spaghetti. Now I find that the GPS152 talks to the Simrad VHF but not to to the old Navico TP300CX tillerpilot. Looking through the manuals, I see that the 152 is NMEA 2.3 while the 120XL was NMEA version 1.5 and 2. I've no idea what the Tillerpilot is. The manual just says NMEA0183 but going by its age, it is unlikely to be 2.3.
I'm going to plug in the old 120XL to test the new wiring connection, but I would welcome advice on whether the 152 is backwards compatible, and can talk to NMEA 1.5 and 2 devices.

 

[LadyInBed]

Have a look at Peter Bennett's GPS Site

 

[Evadne]

The difference would appear to be the autopilot GPx sentences: NMEA 1.5 uses GPA and NMEA uses GPB, scroll down to the tables on this page. So I guess you're stuffed. I hate people who make things backward incomp[atible. On the bright side, there would appear to be nothing wrong with your wiring.

 

[pvb]

The 152 transmits the same NMEA sentences as the 120XL, so it should work with the tillerpilot if the 120XL did. Might be worth trying going into the 152's setup menu and turning off the transmission of Garmin proprietary sentences.

 

[Miker]

Thanks. I've now studied the NMEA info. It appears that Garmin does not send APA or APB sentences and that "The last version 2 iteration of the NMEA standard was 2.3. It added a mode indicator to several sentences which is used to indicate the kind of fix the receiver currently has". I am wondring whether this has stuffed me up. As I said, I'll reconnect the old 120XL and see if it works.

 

[Bilgediver]

I was wondering if anyone remembered Peter......

Peter is an expert on this so an e-mail to him might get help..

John...Just back from Vancouver....Peter Bennettland and home of The Power Boat Squadron ?? /forums/images/graemlins/smile.gif