I have the unit hooked up and functioning now (DB25 was the correct interface connector). I am having a problem with the audio being distorted and a 60 cycle buzz on the audio when it is from the phone to the radio. The buzz is only there with the phone line audio source. The patch test tone is fine...

yes,I have the interconnect eid, but wasn't sure how to physically connect it. IE: wireline board/ 24 pin connector?

The issue is that, even though you have separated the channels onto different speakers, the audio will still mix in the room when played simultaneously on separate speakers. There is no way to separate simultaneous radio traffic in the same room. This leaves select audio and unselect audio to be set...

Anybody interfaced a marti 2000 phone patch to an MTR3000 in digital mode? Looking for technical info on this interface.