1.times.N communication system for private branch exchange

• US 5,884,162 A
• Filed: 07/09/1992
• Issued: 03/16/1999
• Est. Priority Date: 07/10/1991
• Status: Expired due to Fees

• Current Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Original Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Inventors: Yamazaki, Shigeru, Seko, Kazuo, Hiramatu, Akihiko
• Primary Examiner(s): Bost, Dwayne D.
• Assistant Examiner(s): TROST IV, WILLIAM GEORGE
• Application Number:
  US07/910,219
• Time in Patent Office: 2,441 Days
• Field of Search: 379/58, 379/63, 379/156-161, 379/167, 379/168
• US Class Current: 455/416
• CPC Class Codes: H04Q 11/04 for time-division multiplexing H04Q11/0001 takes precedence
• CPC Class Codes: H04Q 2213/13003 Constructional details of switching devices
• CPC Class Codes: H04Q 2213/13058 Interrupt request
• CPC Class Codes: H04Q 2213/13098 Mobile subscriber
• CPC Class Codes: H04Q 2213/13106 Microprocessor, CPU
• CPC Class Codes: H04Q 2213/13194 Four wire connection, transmission
• CPC Class Codes: H04Q 2213/1322 PBX
• CPC Class Codes: H04Q 2213/13292 Time division multiplexing, TDM
• CPC Class Codes: H04Q 2213/1334 Configuration within the switch
• CPC Class Codes: H04W 84/08 Trunked mobile radio systems

Abstract

A press-talk trunk is a communication system receives press-talk signals from voice terminals having press-talk switches. In one aspect of the invention, the press-talk trunk is scanned by a central controller that selects an active press-talk signal and sets up a corresponding 1×N voice communication path among the terminals. In another aspect of the invention, the press-talk truck itself selects an active press-talk signal and notifies the central controller by means of an interrupt. In yet another aspect of the invention, the press-talk trunk also receives voice signals from all the terminals, selects a voice signal from a terminal having an active press-talk signal, and sends that voice signal back to all the other terminals. In still another aspect of the invention, two or more press-talk trunks are cascaded.

Claims

1. A 1×

N communication system, where N is an integer greater than two, comprising;

at least three terminals for sending and receiving voice signals, having respective press-talk switches for generating press-talk signals with active and inactive states;

a time division switching system coupled separately to each of said terminals, for switching communication paths among said terminals;

a press-talk trunk coupled to receive said press-talk signals from said terminals and generate a notification signal when a press-talk signal from any one of said terminals is active, wherein said press-talk trunk comprises I/O ports for respective press-talk signals and said central controller scans said I/O ports; and

a central controller means coupled to said time division switching system for controlling said time division switching system to cause said time division switching system to send voice signals from said one of said terminals to all other of said terminals, responsive to said notification signal.

2. The system of claim 1 wherein, if two or more press-talk signals are active, said central controller means selects a press-talk signal that became active first.

3. The system of claim 1, wherein said press-talk trunk is coupled to said terminals by wires and receives said press-talk signals directly from said terminals.

4. The system of claim 1, wherein at least one of said terminals is portable, and is coupled to said switching system via a wireless link.

5. A 1×

N communication system, where N is an integer greater than two, comprising;

at least three terminals for sending and receiving voice signals, having respective press-talk switches for generating press-talk signals with active and inactive states;

a time division switching system coupled separately to each of said terminals, for switching communication paths among said terminals;

a press-talk trunk coupled to receive said press-talk signals from said terminals and generate a notification signal when a press-talk signal from any one of said terminals is active, wherein said press-talk trunk comprises a discriminator for selecting one active press-talk signal and sending a notification signal for said one active press-talk signal to said central controller; and

a central controller means coupled to said time division switching system for controlling said time division switching system to cause said time division switching system to send voice signals from said one of said terminals to all other of said terminals, responsive to said notification signal.

6. The system of claim 5, wherein said notification signal is an interrupt signal.

7. The system of claim 5, wherein said press-talk trunk selects, from among all active press-talk signals, a press-talk signal that first became active.

8. A 1×

N communication system, where N is an integer greater than two, comprising;

at least three terminals for sending and receiving voice signals, having respective press-talk switches for generating press-talk signals with active and inactive states;

a time division switching system coupled separately to each of said terminals, for switching communication paths among said terminals;

a press-talk trunk coupled to receive said press-talk signals from said terminals and generate a notification signal when a press-talk signal from any one of said terminals is active, wherein said press-talk trunk is coupled to said switching system and receives said press-talk signals from said terminals via said switching system; and

a central controller means coupled to said time division switching system for controlling said time division switching system to cause said time division switching system to send voice signals from said one of said terminals to all other of said terminals, responsive to said notification signal.

9. A 1×

N communication system, where N is an integer greater than two, comprising;

at least three terminals for sending and receiving voice signals, having respective press-talk switches for generating press-talk signals with active and inactive states;

a time division switching system coupled separately to each of said terminals, for switching communication paths among said terminals;

a press-talk trunk coupled to receive said press-talk signals from said terminals and generate a notification signal when a press-talk signal from any one of said terminals is active, wherein said press-talk signals from different terminals are multiplexed by time-division multiplexing; and

a central controller means coupled to said time division switching system for controlling said time division switching system to cause said time division switching system to send voice signals from said one of said terminals to all other of said terminals, responsive to said notification signal.

10. A 1×

N communication system, where N is an integer greater than two, comprising;

at least three terminals for sending and receiving voice signals, having respective press-talk switches for generating press-talk signals with active and inactive states;

a time division switching system coupled separately to each of said terminals, for switching communication paths among said terminals;

a press-talk trunk coupled to receive said press-talk signals from said terminals and generate a notification signal when a press-talk signal from any one of said terminals is active, wherein said press-talk trunk returns to said terminals signals indicating whether 1×

N communication is in progress; and

a central controller means coupled to said time division switching system for controlling said time division switching system to cause said time division switching system to send voice signals from said one of said terminals to all other of said terminals, responsive to said notification signal.

11. A 1×

N communication system, where N is an integer greater than two, comprising;

at least three terminals for sending and receiving voice signals, having respective press-talk switches for generating press-talk signals with active and inactive states;

a time division switching system coupled separately to each of said terminals, for switching communication paths among said terminals;

a press-talk trunk coupled to receive said press-talk signals from said terminals and generate a notification signal when a press-talk signal from any one of said terminals is active, wherein said press-talk trunk returns to each of said terminals a signal indicating whether that terminal is clear for sending voice signals; and

a central controller means coupled to said time division switching system for controlling said time division switching system to cause said time division switching system to send voice signals from said one of said terminals to all other of said terminals, responsive to said notification signal.

12. A 1×

N communication system, where N is an integer greater than two, comprising;

at least three terminals for sending and receiving voice signals, having respective press-talk switches for generating press-talk signals with active and inactive states;

a time division switching system coupled separately to each of said terminals, for switching communication paths among said terminals;

a press-talk trunk coupled to receive said press-talk signals from said terminals and generate a notification signal when a press-talk signal from any one of said terminals is active, wherein said press-talk trunk switches are pushbutton switches; and

a central controller means coupled to said time division switching system for controlling said time division switching system to cause said time division switching system to send voice signals from said one of said terminals to all other of said terminals, responsive to said notification signal.

13. A 1×

N communication system, where N is an integer greater than two, comprising;

at least three terminals for sending and receiving voice signals, having respective press-talk switches for generating press-talk signals with active and inactive states;

a switching system coupled to said terminals, for switching communication paths among said terminals;

a press-talk trunk coupled to said switching system, for receiving said press-talk signals and said voice signals from said terminals via said switching system and, when at least one of said press-talk signals is active, selecting an active press-talk signal from one terminal among said terminals and sending voice signals from that one terminal back via said switching system to other terminals among said terminals.

14. The system of claim 13, wherein said press-talk trunk comprising:

a discriminator for selecting an active press-talk signal; and

a selector controlled by said discriminator, for receiving said voice signals and selecting one of said voice signals for output from said press-talk trunk.

15. The system of claim 13, wherein at least one of said terminals is portable, and is coupled to said switching system via a wireless link.

16. The system of claim 13, wherein press-talk signals from different terminals are multiplexed by time-division multiplexing, and said press-talk trunk also comprises a multiplexer-demultiplexer.

17. The system of claim 13, wherein said press-talk trunk returns to said terminals signals indicating whether 1×

N communication is in progress.

18. The system of claim 13, wherein said press-talk trunk returns to each of said terminals a signal indicating whether that terminal is clear for sending voice signals.

19. A 1×

N communication system, where N is an integer greater than two, comprising;

as least three terminals for sending and receiving voice signals, having respective press-talk switches for generating press-talk signals with active and inactive states;

a slave press-talk trunk means, coupled to receive said voice signals and said press-talk signals from at least two of said terminals, for providing a press-talk signal that is inactive when all received press-talk signals are inactive and active when at least one received press-talk signal is active, for selecting one voice signal corresponding to one active received press-talk signal, and for providing said one voice signal as an output;

a master press-talk trunk means, coupled to received the press-talk signal and the voice signal output from said slave press-talk trunk and at least one other press-talk signal and voice signal, for selecting a voice signal corresponding to one active received press-talk signal, and providing the selected voice signal as an output; and

a switching means for receiving the selected voice signal output from said master press-talk trunk and for routing the selected voice signal to all of said terminals.

20. The system of claim 19, wherein said slave press-talk trunk means and said master press-talk trunk means each comprises:

a discriminator means for selecting an active press-talk signal; and

a selector means, controlled by said discriminator, for receiving said voice signals and selecting one of said voice signals for an output from said press-talk trunk.

21. The system of claim 19, wherein said slave press-talk trunk means is directly coupled to at least two of said terminals.

22. The system of claim 19, wherein said slave press-talk trunk means is coupled to said master press-talk trunk by a wireless link.

23. The system of claim 19, also comprising a higher-order press-talk trunk coupled to receive the voice signal output by said master press-talk trunk means.