Partyline: How do I connect a Sony CCU-M5A to a Clear-Com Partyline system?

The Sony CCU-M5A supports connections to a Clear-Com 2-wire partyline system.  On the rear panel of the CCU-M5A there is a terminal strip and a 4-pin din style connector that supports 2-wire PL connections.  See pictures below:

Connect IC ground to "G"
Connect IC audio to "Y" or "X"