17/19 pin for External GPS UART used to connect OpenIMU with a GPS receiver, and 5/6 pin could connect OpenIMU with MCU or PC with UART data transparent.

The only requirement is that the receiver must be able to output one of the various messages that the openimu firmware can presently accept.
However, as for OpenIMU, user can write their own driver and connect any receiver that they choose.
Currently the OpenIMU have drivers in the firmware for:
• BestPos/BestVel messages (NovAtel type message)
• SiRF Geodetic Navigation Data – Message ID 41 (tested using the OriginGPS ORG4475)
• NMEA GGA and VTG messages
• Ublox (in firmware but untested)

We have already verified the firmware with a NovAtel FlexPak6 receiver using a GPS-700 series antenna.