[arm-allstar] RX Audio only heard when Flashing Red LED is in ON State

[Joshua Hatton]

I am attempting to interface a Pi w/ Allstar to a CAT250 Controller.
I am running into an issue I've never experienced before.

I appear to have success, in the aspect of "operation"... I am able to
send commands to HamVoIP over the controller audio, and able to hear
them, however, the audio received from the Pi/USB Interface is only
heard when the Flashing Red LED of the Interface is in the ON state
(It's not a steady light).  Very odd. There is a measured voltage on
that line as well, as the Red LED maintains a slight dim glow.
Thinking something was wrong with my Masters Comm. RA35 Interface, I
dug out an old URI Interface... It's doing the same thing exactly.
Something is definitely circumstantial with the controller.  Perhaps I
need to do a Pull-up/Pull-Down on **both** the PTT and COR Lines under
the circumstances?
That is pulling one to Pi USB Voltage and the other to controller PSU
voltage?  Just thinking out loud on that.  Wiring made as written
below.

Pi USB Int.  < ---- >  CAT250 Link Port
---------------------------------------------------------------
     PTT   < ---------------- >   COR
     COR  < ---------------- >   PTT
     RXA   < ----------------- >  TXA
     TXA   < ----------------- >  RXA
     GND  < ----------------- >  GND

THanks for any guidance.
Josh W4ZZK