Greetings:

Does anyone have electrical and protocol info for the Si-Tex GPS-5
interface? I connected one of the two data out lines (as traced
from a cable used to connect this GPS to the Si-Tex Nav-Add 7000
Chartplotter) to a PC RS-232 Rx input and using a terminal
emulator program found that the GPS seemed to be talking at
4800 baud, 7-bit, odd parity (as opposed to 8-bit, no parity
as per NMEA-0183 specs). The data stream was either 15 commas
or 7 commas, repeated every second, with no intervening characters.
No antenna is currently connected.

A quick look at NMEA-0183 sentences shows blank data between
commas at certain field positions when no fix is available,
but I didn't see a description of completely empty data and
shouldn't each sentence begin with a dollar sign?

Can anyone verify that the GPS-5 talks NMEA-0183, or that with
no previous or current fix that it would output nothing but
commas?

Thanks,

Michael