Trimble Outdoors SPSX51 - Manual (Page 59)

SPSx51 Modular GPS Receivers User Guide 57
Setting up the Receiver 5
15. Insert the first bolt. Attach the flat washer, the spring washer, and finally the nut
and then tighten firmly. Secure all eight bolts in this way.
16. Attach one connector from the Marine Heading cable (P/N 57169-10) to the
26-pin connector on the rear of the SPS551H GPS receiver. Attach the other
connector from the cable to the 26-pin connector on the rear of the SPSx51
receiver. The cable can be connected either way around.
The cable connects the two GPS receivers so that the Heading solution is
available. The DC power lead on the cable supplies power to both receivers in
the stack. The two DB9 female connectors on the cable access serial port 2 on
each receiver.