Thanks. I don't have the equipment to check the FXO with any certainty but I got a few phones and ran tests with each line and the crosstalk does not occur where a line (any and each) is removed from the PBX and used for incoming or outgoing calls. The noise and crosstalk are much more pronounced on the inside than the outside. If on a call, and another call comes in, the ringing of the other call comes through as a low humm ticking kind of sound, then a very brief noise sounding like a modem handshake and then the voice of the auto attendant.
I've had to revert to the old phone system as no one was able to even have a full conversation without a full disconnect or crosstalk making conversation impossible. As for demarkation, we're in an office building, I'm coming right off the panel less than a foot with standard phone lines to the PBX, the floor demarkation point is only about 30 feet away.
Not sure at this point if the box is a dud or I have it horribly misconfigured, I have not deviated a whole lot from the default configuration. I can't run valid tests now until before/after hours.
/Jeff