Telecommunications – Transmitter and receiver at separate stations – Distortion – noise – or other interference prevention,...
Reexamination Certificate
1999-05-18
2002-07-02
Urban, Edward F. (Department: 2685)
Telecommunications
Transmitter and receiver at separate stations
Distortion, noise, or other interference prevention,...
C062S103000, C062S501000, C062S526000
Reexamination Certificate
active
06415136
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to wireless communication devices, and more specifically to a communication system which prevents interference between wireless devices.
In today's retail environment, there may be many different types of wireless devices, such as wireless data terminals, wireless hand-held scanners, wireless electronic shelf labels, and wireless voice products. Unfortunately, some of these devices may utilize the same RF spectrum, resulting in interference. One of the bands most often used today is the Industrial, Scientific and Medical (ISM) band.
Therefore, it would be desirable to provide a communication system that could eliminate interference between wireless devices.
SUMMARY OF THE INVENTION
In accordance with the teachings of the present invention, a communication system which prevents interference between wireless devices is provided.
The system includes a transmitter, a first transmitter control circuit which allows the transmitter to communicate with a first communication device, a second transmitter control circuit which allows the transmitter to communicate with a second communication device, a first receiver circuit which receive signals from the first communication device, a second receiver circuit which receives signals from the communication device, and a switch circuit.
In a first embodiment, the system additionally includes a first controller coupled to the first receiver circuit and to the first transmitter control circuit which causes the switch circuit to select the first transmitter control circuit during a first time period, and a second controller coupled to the second receiver circuit and to the second transmitter control circuit which causes the switch circuit to select the second transmitter control circuit during a second time period different than the first time period.
In a second embodiment, the system additionally includes a controller coupled to the first and second receiver circuits which causes the switch circuit to select the first transmitter control circuit during a first time period and the second transmitter control circuit during a second time period different than the first time period.
In either embodiment, switching may be controlled by the wireless devices or by first and second host systems that use the transmitter to communicate with the wireless devices. When the host systems initiate communications with the first and second wireless devices, the controller or the first and second host systems change the switch accordingly. When the first and second wireless devices initiate communications with the first and second host systems, the controller or the first and second host systems also change the switch accordingly.
It is accordingly an object of the present invention to provide a communication system which does not suffer from interference between wireless devices.
It is another object of the present invention to provide a communication system which does not suffer from interference between wireless devices, and which includes a multi-mode transceiver.
It is another object of the present invention to provide a communication system which does not suffer from interference between wireless devices, and which includes a multi-mode transceiver with a multi-mode transmitter portion that operates in only one mode at a time.
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Patent Abstracts of Japan, vol. 1996, No. 05, May 31, 1996, and JP 08 023564 A (NEC Corp), Jan. 23, 1996, abstract.
Martin Paul W.
NCR Corporation
Urban Edward F.
Zewdu Meless
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