Method and apparatus for the connection of a closed ring through a telephone exchange

• US 4,715,032 A
• Filed: 01/16/1985
• Issued: 12/22/1987
• Est. Priority Date: 06/09/1983
• Status: Expired due to Fees

• Current Assignee: Telefonaktiebolaget LM Ericsson
• Original Assignee: Telefonaktiebolaget LM Ericsson
• Inventors: Nilsson, Olof E.
• Primary Examiner(s): Ng, Jin F.
• Assistant Examiner(s): Scutch, III, Frank M.
• Application Number:
  US06/692,029
• Time in Patent Office: 1,070 Days
• Field of Search: 370/86, 370/89, 370/90, 340/825.05, 340/825.06, 340/825.07
• US Class Current: 370/383
• CPC Class Codes: H04L 12/43 with synchronous transmission, e.g. time division multiplex [TDM], slotted rings
• CPC Class Codes: H04Q 11/04 for time-division multiplexing H04Q11/0001 takes precedence

Abstract

A method and apparatus which relate to a digital telecommunication system in which information is transferred between terminals (T1-Tn) connected to a telephone exchange for establishing a ring with the aid of a loop connection to enable sending data between arbitrarily selected terminals. Each of the terminals includes at least one send channel and one receive channel.

Such a telecommunication system includes a plurality of terminals connected via time multiplexed channels to an exchange of the stored program control type (SPC), in which the switching functions are controlled by software. The terminals may have telephone sets, display units, etc. Control units and separate computers can also be connected to the exchange. A transfer with the aid of the exchange is made, from an arbitrary terminal to the next terminal in a serial loop or ring irrespective of between which terminals connection is desired. The information to be sent from one terminal to another thus goes via all terminals connected to the loop. The loop is set up with the aid of the exchange in such a way that the send output (S) of a preceding terminal is connected to the receive input (R) of the next terminal, etc. such that a closed ring is obtained, enabling a terminal anywhere within a PABX to be connected to another optional unit.

Claims

1. In the utilization of a digital telecommunication system including an exchange including connecting circuits adapted for being controlled by signals, and a plurality of terminals including at least three terminals, each of said terminals including a send channel and a receive channel, a method of connecting the terminals in a closed loop so that any pair of terminals can communicate comprising the steps of physically connecting the channels of each terminal to the exchange, and establishing communication between any pair of said terminals by coupling all of the terminals in series in a closed loop such that the pair of terminals communicate with each other through intervening of said terminals in said loop, said establishing communication being effected by connecting the send channel of each of the terminals to the receive channel of the next sequential of the terminals in said loop by controlling the connecting circuits of the exchange to connect the same until said closed loop is formed, transmitting from each terminal of the pair to the other terminal of the pair through said loop, and adding a further terminal to said loop by physically connecting the further terminal to the exchange and, within the exchange, signalling the connecting circuits to connect the send and receive channels of the further terminal respectively to the receive and send channels of two other terminals in the loop so as to include the further terminal in the loop.

2. The method of claim 1 comprising in addition to the loop, providing speech channels between the terminals and the exchange, and transmitting speech signals via the speech channels and transmitting data via the loop.

3. The method of claim 1 further comprising the steps of providing other terminals connected to another exchange in the form of another loop and interconnecting the terminals and exchanges to provide a combined loop.

4. In a digital telecommunication system including a plurality of terminals each including a send channel and a receive channel, and an exchange including connecting circuits adapted for being controlled by signals connecting the channels to form a closed loop, the improvement whereby said exchange comprises:

an input buffer means including a plurality of addressed registers each including an input connected to the send channel of a different terminal for receiving information signals therefrom, an addressing means for selecting an address register and an output register for receiving signals from the thusly selected addressed registers;

an output buffer means including an input register, a plurality of addressed registers each including an output connected to the receive channel of a terminal for transmitting information thereto, and an addressing means for selecting an addressed register, each of said addressed registers accepting information signals stored in said input register when selected;

bus means connecting said output register to said input register;

a control store means including a plurality of addressed registers for storing addresses of the addressed registers of said output buffer means, an addressing means for selecting an addressed register, and an output register for receiving signals from the thusly selected addressed registers; and

means for connecting the output register of said control store means to the addressing means of said output buffer means;

counter means sequentially generating addresses; and

means for connecting said counter means in parallel to the addressing means of said input buffer means and the addressing means of said control store whereby information read from an addressed register of said input buffer means is transmitted to the addressed register of said output buffer means specified by the address being simultaneously read from the addressed register of said control store means having the same corresponding address of the selected addressed register of said input buffer means.

5. The improvement of claim 4 further comprising a plurality of line pair means for two-way voice communication, each of said line pair means connecting a different one of said terminals to said exchange.