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Ericsson GPS 03 01
The Ericsson GPS 03 01 is very similar to the Nokia FYGM in that it is a GNSS-disciplined time reference for cell site equipment. The osmocom wiki has a page with great information about it here: https://osmocom.org/projects/ericsson-rbs-6xxx/wiki/GPS_02
GNSS
The GNSS module in the GPS 03 01 is the Trimble 97975-01 aka RES SMT 360.
Hardware
The GPS 03 01, like the 02 01 and 04 01, is in an enclosure made from two pieces of galvanized sheet steel that have been folded into half boxes and riveted together through the center. If you wish to use it as-is, there are two RJ-45 connectors on the box that provide identical signals for NMEA in/out, power in, and PPS out. Like the Nokia FYGM, these signals do not come directly from the GNSS module, but from a separate microcontroller - in this case, an STM32F105RCT6, which is a very powerful chip. Unfortunately, it does not seem to have a programming interface exposed.
The pinout for the RJ45 connectors is as follows:
| Pin | Description | Color (ethernet wires) |
|---|---|---|
| 1 | 1PPS+ | |
| 2 | 1PPS- | |
| 3 | RxD+ | |
| 4 | TxD+ | |
| 5 | TxD- | |
| 6 | RxD- | |
| 7 | +12v | |
| 8 | GND |