[aprssig] Deluo GPS connector

[KC2MMi]

FWIW, DeLuo refer to their PS/2 connector (in their data sheets, etc.) with
pins 1/6 top, pins 3/4 bottom. This is to match the standard laptop PS/2
port, which they use to supply power (and power only) for their serial
GPSes. They use a split serial+ps/2 cord, intending to pick up the data on
the serial port and the power from the PS/2. Apparently this is standard
across their line now, all same orientation and pinout, although some of the
pinouts also show data lines and have 4 wires running in them. (Puzzling, no
idea how they expect to get data via the PS/2 plug!)