Brother IntelliFAX 2800 help!!!!!?

Hello, I have a Brother IntelliFAX 2800 (fax machine) at work, and also works as the main telephone. Problem is, about every 3 minutes, there is some sort of "pause", more like the call has been lost, I can not hear or can be heard by the other party, it has been like that since we got it. Yesterday I got a call from the CEO in person (I answer the phones!!!) and he asked for my boss, I said (he is not in rigth now... and the phone went dead for 3 seconds (one mississippi... two mississippi... three mississippi...) and OF COURSE HE HANG UP REALLY MAD!!!!! He thouth I hang up on him!!!!!
PLEASE, I want to fix that feature in the fax. I am guessing is something very simple, maybe like changing the volume or choosing features for the fax.
The phone line is fine, we conected other phones and work perfect. Also the other girls on other floors and buildings have the SAME PROBLEM WITH THE same kind of FAX MACHINE!!! someone knows how to fix it????????????

it sounds as if the fax is set to listen for a fax tone and it is listening for the tone when you have the line off hook,

get a cheap phone and plug it into the line port on the fax or get a splitter to split the dial tone, this will remove the fax pause problem.