I have a branch router that has an ISDN PRI as its main line and
a couple of FXS cards. The main location has our Call Manager. We have a FAX maching plugged into one of the FXS ports at the branch location. Our 4 digit extensions match the last 4 digits of their DID.
What is the best way to configure this fax machine to send and recieve calls both internal as well as external? And use its DID to the PSTN. I would rather not use MGCP.