Hello. I have one station that after picking up the headset or hitting the speaker button and hitting "9" to get an outside line. It would get CO however when trying to enter in any number beside 9, no response.

I have compare station programming to my extension since it worked however both are the same. Not sure what I am missing? any suggestion? I'm sure its an easy fix. Thank you

Silly question, but have you swapped phones

I would agree that this would be the best place to start. Also, is the phone set up with the headset mode active?