METHOD AND APPARATUS FOR DETECTING A FACSIMILE TRANSMISSION

• Main Authors: JOHN, JOHNNY, K, SIH, GILBERT, C
• Format: Patent
• Language: English; French; German
• Published: 05.04.2006
• Subjects: ELECTRIC COMMUNICATION TECHNIQUE; ELECTRICITY; PICTORIAL COMMUNICATION, e.g. TELEVISION; SELECTING; TELEPHONIC COMMUNICATION

A novel and improved method and apparatus for providing an interface to a digital wireless telephone system compatible with standard analog wire line telephones and analog wire line fax machines is disclosed. During a telephone call, a fax detector (11) monitors the incoming data for fax signals. If a fax is detected, the data processor (12) switches from processing the data as if it were voice to processing it as fax. In addition, the remote station is sent a signal notifying it to process the data as fax rather than voice. The fax detector (11) operates by detecting the preamble of a V.21 message, present at the beginning of every fax call. Energy is measured in both frequencies of the BFSK signals. A decision is made by analyzing these energies and locating a specific pattern which repeats itself a sufficient number of times.