1. A method for increasing the compatibility of a fax machine, comprising: providing in a first fax machine a plurality of protocol modules each supporting a facsimile transmission protocol for communicating with other fax machines; receiving in the first fax machine information from a second fax machine identifying the capabilities and a facsimile transmission protocol of the second fax machine; determining whether the second fax machine is compatible with a protocol module in the first fax machine; if the second fax machine is compatible with a protocol module in the first fax machine, then: interpreting the capabilities of the second fax machine by using the protocol module in the first fax machine that is compatible with the second fax machine to read the information identifying capabilities provided by the second fax machine; and communicating between the first and second fax machines using the protocol module in the first fax machine compatible with the second fax machine to implement the facsimile transmission protocol.