Electronic facsimile machines, often called fax machines, are in widespread use. Such machines transfer images from one location to another location electronically over a normal telephone line. Likewise voice mail systems are in widespread use. Such systems answer telephones and store messages for later retrieval.
Recently systems have become available which merge voice mail technology and facsimile technology. Such systems provide what is termed "fax store and forward" services. For example see U.S. Pat. No. 5,008,926 issued Apr. 16, 1991 and U.S. Pat. No. 4,837,798.
The present invention solves a particular problem which arises when a "fax store and forward" system is connected to a PBX system. In such systems, if a fax machine is busy when the machine is called, the call is re-directed to the fax store and forward system. Later the store and forward system utilizes one of its ports to call the fax machine to deliver the fax. If the fax machine is still busy, the call will be redirected back to a different port of the store and forward system and without the special precautions, the fax would be stored a second time. The present invention is directed to eliminating the problems which arise when the same fax message is re-directed to a fax store and forward system, multiple times.