Cordless telephone system

• US 4,744,101 A
• Filed: 05/18/1987
• Issued: 05/10/1988
• Est. Priority Date: 05/31/1986
• Status: Expired due to Term

• Current Assignee: NEC Corporation
• Original Assignee: NEC Corporation
• Inventors: Saegusa, Noboru
• Primary Examiner(s): Lev, Robert
• Application Number:
  US07/051,486
• Time in Patent Office: 358 Days
• Field of Search: 379/61, 379/62, 379/59, 379/60, 379/63, 379/58, 379/56, 455/33, 455/54
• US Class Current: 455/464
• CPC Class Codes: H04M 1/72511 Searching for available channels

Abstract

A cordless telephone system constituted by a switching station connected to a cable telephone exchanger and at least one telephone set connected to the switching station via a plurality of radio channels. The switching station has a controller which scans the radio channels and selects a nonused radio channel in response to a calling signal from the telephone exchanger, a signal generator for calling a telephone set, a signal detector for detecting a response signal from the telephone set, and a transmitter. The controller changes the number of radio channels to be scanned in accordance with the frequency of use of the radio channels and the transmitter sends a signal representing a changed number of radio channels. Each telephone set has a controller for scanning the radio channels, a signal detector for detecting the calling signal and the signal representing the number of channels from the switching station, and a transmitter for sending a response signal to the switching station.

Claims

1. A cordless telephone system constituted by a switching station connected to a telephone exchanger and at least one telephone set connected to said switching station via a plurality of radio channels;

said switching station comprising means for scanning the radio channels, means, responsive to a calling signal from said telephone exchanger, for selecting a nonused radio channel, signal generating means for calling a telephone set, means for detecting a response signal from said telephone set, means for changing the number of radio channels to be scanned in accordance with a frequency of use of the radio channels, and means for sending a signal representing a changed number of radio channels; and

each telephone set comprising means for scanning the radio channels, means for detecting the calling signal and the signal representing the number of channels from said switching station, and means for sending a response signal to said switching station.

2. A system according to claim 1, wherein said telephone set further comprises means for periodically turning off a power source of a receiver in accordance with the signal representing the number of radio channels.