Quick google search shows one reference to it being NMEA 0183 specifically it's looking for the GPGGA message which gives time, lat, long, and alt.
One of the setup manuals I found for Synscan showed a step by step guide of setting up a commercial unit to work with a Synscan hand controller.
Good bits from that manual are that the GPS unit was configured with a baud rate of 4800bps, NMEA output, and on the output dump window the only command which showed a GPS coordinate was a GPGGA message.
http://thadlabs.com/FILES/SynScan_GP...v_B_101906.pdf
Additionally another link detailing the setup to Eqmod on the PC said that eqmod works with several messages but had the interesting note that GPGGA can be configured on some units to give a timezone corrected output, and for eqmod it has to be UTC. I imagine if the time is incorrect on the synscan after you plug your GPS in that would be a good thing to check.
