xerox workcentre 7235 Fax cover page shows the wrong fax number

Hello,

I've got a xerox workcentre 7235 that seems to send the wrong phone number on faxes. The recipient of the fax gets a number on the fax cover page that is not the xerox's fax number. 

Is the number that shows up on the receiving end's cover page programmable? 

Thanks in advance for the help.