... . Dual TTL level serial ports with one for GPS receiver command message interface, another one for RTCM-104 DGPS input. Compact Board Size ... GPS Timing Multi-path Mitigation Hardware On-board RTCM SC-104 DGPS and WAAS /EGNOS Demodulator Built-in a lithium battery ... (VTG, GLL and ZDA for optional)). DGPS protocol RTCM SC-104 message types 1, 2 and 9. SiRF binary-position, velocity ...