[Motorola] Motorola MCX1000 Diagnostic Test Plug

[Eric Lemmon]

I have a couple of Motorola MCX1000 VHF trunk-mount radios, that I finally
am getting around to testing.  A friend gave me a copy of the Service Manual
68P02902A56, so I am good to go.

In the Maintenance and Alignment section of the manual, it calls out a
"Diagnostic Test Plug" part number 0180358A54.  This device is plugged into
the mike jack before cycling the power to the radio, and the radio comes up
in a special test mode.  I looked up the part number on MOL, and found it
described as "MCX1000 Modular Plug" but it has been cancelled.

This may be nothing more than a garden-variety 8-wire modular plug, with
some jumpers installed.  I know that the MCX1000 radio has separate Bus+,
Bus-, and Busy signal wires in the mike jack, so this may be some sort of
loopback plug.  Does anyone know how this Test Plug is wired?

73, Eric Lemmon WB6FLY