Small modular communications switching system with distributed programmable control

• US 3,974,343 A
• Filed: 01/10/1975
• Issued: 08/10/1976
• Est. Priority Date: 01/10/1975
• Status: Expired due to Term

• Current Assignee: Alcatel SA (Nokia Corporation)
• Original Assignee: North Electric Company
• Inventors: Kuczura, Anatol, Cheney, Thomas K.
• Primary Examiner(s): Brown, Thomas W.
• Application Number:
  US05/540,077
• Time in Patent Office: 578 Days
• Field of Search: 179/18 ES
• US Class Current: 379/244
• CPC Class Codes: H04Q 3/545 using a stored programme

Abstract

A telephone central office switching system with economical application to small community dial office sizes is disclosed. Communication paths are spatially switched over a modular network fabric comprised of electromechanically actuated metallic crosspoints. A distributed control concept is employed wherein the logic power and flexibility of electronic stored program control is spread over many points in the system. Serial asynchronous messages between any two control elements are routed via a central information exchange unit whose number of communication ports is easily changed on a pluggable basis. Modularity is emphasized throughout the switching system for facile growth and additions of feature-oriented service packages.

Claims

1. In a communication switching system, a plurality of lines, a plurality of switching network means for selectively interconnecting said lines, each of said switching network means including discrete stored program control means permanently associated therewith, information exchange means comprising a dedicated stored program control means and at least one memory means for storing system routing translation data, information transmission means connecting said information exchange means to said discrete stored program control means for said switching network means, a plurality of service circuit means, each of which is connected to each of said switching network means, and each of which includes a dedicated stored program control means permanently associated therewith, and means connecting said dedicated stored program control means of each of said service circuit means to said information exchange means for use in the establishment of a communication path over said switching network means.

2. A communication switching system as set forth in claim 1 in which each of said plurality of switching network means comprises a module connected to a different group of said lines, each of said modules includes a plurality of switches for completing switching paths in its module, and in which the discrete stored program control means for each module includes first processor means for scanning the group of lines associated with its module, second processor means for selectively operating said switches to selectively complete paths in its associated module, and third processing means for providing a status record of the switching paths in said module.

3. A communication switching system as set forth in claim 2 which includes first path means connecting said second processor means and said first processor means, second path means connecting said third processor means and said second processor means, and further means for connecting said second processor means to said information transmission means.

4. A communication switching system as set forth in claim 3 in which said first processor means includes a plurality of line control means having memory means for storing the current state, class marks, and number group translation information for each of said lines for said module.

5. A communication switching system as set forth in claim 3 in which said information transmission means includes a serial-by-bit bus for exchanging information between said information exchange means and discrete stored program control means in an asynchronous mode.

6. A communication switching system as set forth in claim 3 in which said information transmission means includes receiver-transmitter means operative to generate an interrupt signal for presentation over said further means to said second processor means responsive to the receipt of information from said information exchange means.

7. A communication switching system as set forth in claim 1 in which each of said discrete stored program control means for said switching network means includes processor means for scanning the group of lines connected to its switching network means, and means connecting the processor means for one of said switching network means to the processor means for at least one other of said switching network means for selective use in scanning of the lines of said other switching network means.

8. A communication switching system as set forth in claim 1 wherein said means which connect said dedicated stored program control means of each of said service circuit means to said information exchange means includes serial-by-bit bus means.

9. A communication switching system as set forth in claim 1 in which at least one of said switching network means includes at least one trunk circuit connected thereto, and in which said service circuit means includes at least one incoming register means for processing requests for services received over said switching network means from said trunk circuit, at least one sender means for transmitting call information over said switching network means to further switching systems, and at least one originating register means for processing requests for service received over said switching network means from said lines.

10. A communication switching system as set forth in claim 9 in which said information exchange means is operative in response to a signal request from said originating register means to transmit a code to a selected one of the switching network means which identifies the one of the switching network means to be selected for use in the extension of a communication path.

11. A communication switching system as set forth in claim 9 in which said originating register means is operative in response to signals received from one line in one of said switching network means which identifies a further line in the system to enable said information exchange means to transmit the identification of the one of the switching network means which is connected to said further line to the discrete stored program control means in said one switching network means.

12. A communication switching system as set forth in claim 11 in which at least one of said switching network means includes a plurality of outlets, an intramodule junctor circuit connected to a first and a second one of said outlets, an intermodule junctor circuit connected to a further one of said outlets, and in which said discrete stored program control means for said one switching network means is operative to select one of said junctor circuits in accordance with the switching network means which is identified as being connected to said further line.

13. A communication switching system as set forth in claim 1 in which said switching network means includes a plurality of inlets having lines connected thereto, and in which said discrete stored program control means for each switching network means includes means for translating directory number information received from said information exchange means to inlet identification signals for use in selecting the inlet identified by said signals.

14. A communication switching system as set forth in claim 1 in which each of said switching network means comprises a separate module, and each of which includes switches which are selectively operated by the discrete stored program control means for its associated module, and means for connecting the discrete stored program control means for one of said switching network means to control the switches in another of said switching network means.

15. A communication switching system as set forth in claim 1 in which at least one of said switching network means includes a plurality of inlets, each of which has a different one of said lines connected thereto, a plurality of outlets, and at least one intramodule junctor circuit connected to two of said outlets for use in extending switching paths between said inlets.

16. A communication switching system as set forth in claim 15 which includes at least one intermodule junctor circuit connected to at least one other of said outlets and an outlet on a further one of said switching network means for extending switching paths between said one and said further switching network means.