What is the talker ID of this GPS receiver?
NMEA is used to connect several kinds of marine equipment with a PC, GPS is just one of these. GPS receivers should identify themselves as "GP". (GLONASS has "GL" as talker ID.)  

Example GGA sentence:  

$GPGGA,123519,4807.038,N,01131.000,E,1,08,0.9,545.4,M,46.9,M,,*47