My customer has a fax machine that keeps going off hook. It's on an analog port on a Nortel BCM 400 (ASM not ATA). We know it's going off hook because when the notice they have stopped receiving faxes they plug in an analog phone and tap the flash until they get dial tone. We have moved to a new switch port and replaced the cord. Fax vendor has replaced the boards.
It sounds to me like the fax machine is not releasing the line by disconnecting all the way-- could this possibly be the jack/cabling?
One more thing- we get our incoming "T1" phone service from a Cisco Call Manager which is our local CO.
Trouble shooting suggestions would be appreciated. Thanks!

Do you happen to have another fax machine that you can swap it out with, at least temporarily, to see if the issue goes away or moves with the existing machine?

Is the Cisco providing a positive disconnect so that everything releases properly?

I "FEATURE 00"

Could it possibly be connected to an alarm line? I had an alarm do that to me once.

Do you know if your circuits are ground or loop start?

A Tek-Tip Lover

It could be polarity sensetive