What is the pin out of comm 3 on a CM9760-KBD Intelligent keyboard?

Issue

Unknown pin out of comm 3 on a CM9760-KBD Intelligent keyboard.

Product Line

Pelco Matrix

Environment

CM9760-KBD Intelligent Keyboard

Cause

Hook up an alternate connection from the COM 3 on the keyboard to COM 1 on the CM9700-CC1.

Resolution

Comm 3 is a RS232 port:
Pin 1 is TX out
Pin 2 is RX in
Pin 3 is not used
Pin 4 is ground