Portable-to-portable talk system for cordless telephone

• US 5,247,567 A
• Filed: 04/29/1992
• Issued: 09/21/1993
• Est. Priority Date: 05/20/1991
• Status: Expired due to Fees

• Current Assignee: Pioneer Communications Corp. (Pioneer Corporation), Pioneer Electronics (USA) Incorporated (Pioneer Corporation)
• Original Assignee: Pioneer Electronics (USA) Incorporated (Pioneer Corporation), Premier Communications Corporation
• Inventors: Hirano, Masahiro
• Primary Examiner(s): Ng, Jin F.
• Assistant Examiner(s): Cumming, William D.
• Application Number:
  US07/875,416
• Time in Patent Office: 510 Days
• Field of Search: 379/56, 379/58, 379/59, 379/60, 379/61, 379/201, 379/210, 379/211, 379/212, 455/31.1, 455/33.1, 455/33.2, 455/39, 455/49.1, 455/53.1, 455/54.1, 455/73, 455/78
• US Class Current: 455/463
• CPC Class Codes: H04M 1/72508 using a control channel
• CPC Class Codes: H04M 1/72511 Searching for available channels

Abstract

A portable-to-portable talk system for cordless telephone. The transmitter-receiver of base unit has a control channel and a plurality of talk channels. The transmitter-receiver transmits the channel number of a vacant talk channel to a first portable unit and to a second portable unit over the control channel upon reception of a connection request from the first portable unit over the control channel. The transmitter-receiver is then switched from the control channel to the vacant talk channel after having transmitted the channel number of vacant talk channel over the control channel. Then, the receiver output of the transmitter-receiver is connected to the transmitter input. The transmitter-receiver of the portable unit has the control channel and the plurality of talk channels and transmits the connection request to the base unit over the control channel. The transmitter-receiver of portable unit is switched from the control channel to the vacant talk channel upon reception of the channel number of vacant talk channel from the base unit. A Tx/Rx selecting signal is transmitted over the vacant talk channel to other portable unit via the base unit when an operator of portable unit completes his speech. The second transmitter-receiver operates as a receiver when the Tx/Rx selecting signal is outputted from the local portable unit, and as a transmitter upon reception of the Tx/Rx selecting signal from other portable unit so that an operator is permitted to begin his speech.

Claims

1. A portable-to-portable talk system for cordless telephone where a base unit and portable units are linked via a radio transmitter-receiver, said base unit comprising:

a first transmitter-receiver having a control channel and a plurality of talk channels;

a portable-to-portable line setting section for causing said first transmitter-receiver to transmit a channel number of a vacant talk channel selected from said plurality of talk channels to a first portable unit and to a second portable unit over said control channel upon reception of a connection request from said first portable unit over said control channel,

said portable-to-portable line setting section causing said first transmitter-receiver to switch from said control channel to said vacant talk channel after said channel number of vacant talk channel is transmitted from said first transmitter-receiver over said control channel,

said portable-to-portable line setting section connecting a receiver output of said first transmitter-receiver to a transmitter input of said first transmitter-receiver after said channel number of vacant talk channel is transmitted to said first and second portable units;

each of said plurality of portable units comprising;

a second transmitter-receiver having said control channel and said plurality of talk channels, said second transmitter-receiver transmitting said connection request to said base unit over said control channel when requesting a connection to other portable unit, said second transmitter-receiver being switched from said control channel to said vacant talk channel upon reception of said channel number of vacant talk channel from said base unit over said control channel;

A Tx/Rx selecting signal generator for generating a signal commanding a switching of said second transmitter-receiver between Tx mode and Rx, said Tx/Rx selecting signal being transmitted over said vacant talk channel to other portable unit via said base unit when an operator of portable unit completes his speech;

a Tx/Rx selector for causing said second transmitter-receiver to operate as a receiver when said TX/Rx selecting signal is outputted from said TX/Rx selecting signal generator, said Tx/Rx selector causing said second transmitter-receiver to operate as a transmitter upon reception of said TX/Rx selecting signal from other portable unit via said base unit over said talk channel so that an operator is permitted to begin his speech.