Telephonic communications – Telephone line or system combined with diverse electrical... – To produce visual-graphic copy
Reexamination Certificate
1999-03-11
2001-08-21
Chan, Wing F. (Department: 2643)
Telephonic communications
Telephone line or system combined with diverse electrical...
To produce visual-graphic copy
C379S093090, C379S100150, C455S557000, C358S442000
Reexamination Certificate
active
06278775
ABSTRACT:
BACKGROUND OF THE INVENTION
I. Field of the Invention
The present invention relates to communications systems. More particularly, the present invention relates to a novel and improved method for automatically detecting a fax call and providing the correct service option based on that detection.
II. Description of the Related Art
Digital wireless telephone systems allow information to be exchanged more efficiently than analog wireless telephone systems. This increased efficiency allows a greater number of telephone calls or other communications to be conducted over digital wireless telephone systems using a given amount of radio frequency (RF) bandwidth. A prominent example of an analog wireless telephone system is the AMPS cellular telephone system employed extensively throughout the United States.
In some instances, the increased efficiency provided by digital wireless telephone systems is so substantial that digital wireless telephone service becomes economically competitive with the traditional analog wire line telephone service. Analog wire line telephone service is the telephone service provided using the conventional wire based telephone system, often referred to as the public switched telephone network (PSTN). Analog wireline telephone systems typically process data in analog format directly, or in a digital representation of the analog data referred to as pulse code modulated (PCM) format. Analog wire line telephone service has traditionally been far less expensive than wireless telephone service.
To provide a complete replacement for traditional analog wire line telephone service, wireless digital telephone systems must be able to accommodate all the services and functions that are currently supported by analog wire line telephone service. One such service is fax transmission.
Although digital wireless telephone systems typically do provide fax transmission service, the interface to the fax service is generally different than that of analog telephone systems. In particular, digital wireless telephone systems process the digital data directly, rather than in the form of tones, as practiced for analog communication systems.
Because of the different interface methods, some analog telecommunication equipment can not be used with the digital wireless telephone systems. In particular, fax machines designed for use with an analog telephone system typically cannot be used with a digital wireless telephone system. Therefore, a user converting from analog wire based telephone service to digital wireless telephone service will have to consider the capital investment made in such equipment when determining the cost benefit of switching to digital wireless telephone service.
Therefore, to reduce the cost of transitioning from wire based telephone service to a digital wireless telephone service, it is desirable to provide interface to a digital wireless telephone system that works with analog based wire line telecommunication equipment. In particular, it would be desirable to provide an interface to a digital wireless telephone system that works with standard telephones and fax machines.
SUMMARY OF THE INVENTION
The present invention is 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. During a telephone call, a fax detector monitors the incoming data for fax signals. If a fax is detected, the data processor 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 operates by detecting a known pattern that is present at the beginning of every fax call. During the initiation of a fax call, certain parameters are negotiated between the transmitting and the receiving fax machines. These parameters are transmitted as BFSK signals consisting of a preamble followed by the parameter data. The preamble is the known pattern which can be detected. 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.
REFERENCES:
patent: 5022071 (1991-06-01), Mozer et al.
patent: 5117453 (1992-05-01), Piasecki et al.
patent: 5267301 (1993-11-01), Nishii
patent: 5323398 (1994-06-01), Wake et al.
patent: 5448378 (1995-09-01), Matsumoto
patent: 5450472 (1995-09-01), Brax
patent: 5892816 (1999-04-01), Sih et al.
patent: 2169174 (1986-07-01), None
“Recommendation V.21” CCITT 1984, pp. 65-69.
John Johnny K.
Sih Gilbert C.
Chan Wing F.
Kalousek Pavel
Qualcomm Inc.
Wadsworth Philip
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