4
reset and start searching for satellites.
* SELECT :
Do not connect.
* TXA :
This is the main transmits channel for outputting navigation and measurement data to user’s
navigation software or user written software.
MTI-1(TTL): TTL level , 0V ~ 3.5V
MTI-1(RS232): RS232 level
* RXA :
This is the main receive channel for receiving software commands to the engine board from
SiRFdemo software or from user written software.
Normally this pin must be kept in high, and if you don’t use this pin please connect a resistor to
3.5V to pull high.
* TXB :
No function as so far (Do not connect)
* RXB :
This is the auxiliary receive channel for inputting differential corrections to the engine board to
enable DGPS navigation.
* Time mark :
This pin provides one pulse-per-second output from the engine board that is synchronized to
GPS time.
* GND :
GND provides the ground for the engine board. Connect all grounds.
* Others :
Do not connect.
2. SOFTWARE COMMAND
2.1 NMEA Output Command
GGA-Global Positioning System Fixed Data
