Peripheral communications network

• US 5,305,320 A
• Filed: 10/06/1992
• Issued: 04/19/1994
• Est. Priority Date: 10/06/1992
• Status: Expired due to Fees

• Current Assignee: American Telephone & Telegraph Company (AT&T, Inc.)
• Original Assignee: AT&T, Inc.
• Inventors: Woods, Gordon D., Brolin, Stephen J., DeMarco, Robert W., Andrews, Michael W., Greenberg, Daniel S., Sarkar, Chandan, Hodgdon, David J.
• Primary Examiner(s): Safourek, Benedict V.
• Application Number:
  US07/953,571
• Time in Patent Office: 560 Days
• Field of Search: 370/85.1, 370/85.2, 370/85.6, 370/85.8, 370/94.3, 370/110.1, 370/100.1, 370/111, 370/119, 370/85.3, 370/85.7, 370/85.15, 375/7, 375/8, 375/121
• US Class Current: 370/229
• CPC Class Codes: H04L 12/44 Star or tree networks
• CPC Class Codes: H04Q 11/04 for time-division multiplexing H04Q11/0001 takes precedence

Abstract

Disclosed is a communications network for peripherals in a digital loop carrier transmission system. A broadcast STAR network is employed so that all peripherals receive any message which is broadcast by any of the peripherals. No peripheral broadcasts without clearance from the active communications hub. Two hubs can be provided to alternatively act as the active hub. Each peripheral includes a controller which transmits a request to send signal, multiplexes the request to send signal with an outgoing message, receives clear to send signals, and demultiplexes the clear to send signals from an incoming message.

Claims

1. A circuit in a peripheral component for use in a digital loop carrier transmission system employing a broadcast STAR network for communication among peripheral components of the system, the circuit comprising:

a microprocessor including a peripheral controller, the controller including means for transmitting an outgoing message stream to a hub, means for transmitting to the hub a signal indicating a request to send a message to other peripherals of the system, means for receiving a signal indicating it is clear to send said message, and means for processing an incoming message stream from the hub in order to determine if said incoming message stream is intended for the peripheral including the circuit;

means for multiplexing the request to send signal with the outgoing message stream; and

means for demultiplexing the clear to send signal from an incoming message stream.

2. The circuit according to claim 1 further comprising a synchronization circuit coupled between said controller and said multiplexer and demultiplexer.

3. The circuit according to claim 1 further comprising a delay compensator circuit coupled between said controller and said multiplexer and demultiplexer, said circuit removing the clear to send signal to the controller as soon as the request to send signal is removed from the outgoing message stream.

4. The circuit according to claim 1 wherein the microprocessor further comprises a core central processing unit.

5. The circuit according to claim 1 wherein the means for transmitting a request to send signal and for receiving a clear to send signal comprise a flow control circuit.

6. The circuit according to claim 1 wherein the means for transmitting an outgoing message stream and for processing an incoming message stream comprises a high level data link control transceiver coupled to a memory through a direct memory access circuit.

7. The circuit according to claim 6 wherein the transceiver includes an address match circuit for determining if the incoming message is intended for the peripheral.

8. The circuit according to claim 1 wherein the means for multiplexing is capable of multiplexing the request to send signal and message stream into a synchronization time slot of the system.

9. A circuit for use in a digital loop carrier transmission system employing a broadcast STAR network for communication among peripheral components of the system, the circuit comprising

means for receiving message streams from the peripherals;

means for scanning the message streams to determine the presence of a request to send signal;

means for selecting the message stream of a peripheral including a request to send signal for transmission to all peripherals of the system; and

means for transmitting a clear to send signal to the selected peripheral.

10. The circuit according to claim 9 further comprising a timing generator coupled to said scanning means.