REMOTE DIGITAL SWITCHING TECHNIQUE FOR USE ON COMMUNICATIONS CIRCUITS

• US 3,814,839 A
• Filed: 05/08/1972
• Issued: 06/04/1974
• Est. Priority Date: 05/08/1972
• Status: Expired due to Term

• Current Assignee: General Signal Corporation (SPX Corporation)
• Original Assignee: Andre Lubarsky Jr, Richard E. Pospisil
• Inventors: Lubarsky, Andre Jr., Pospisil, Richard E.
• Primary Examiner(s): Brown, Thomas W.
• Application Number:
  US05/251,353
• Time in Patent Office: 757 Days
• Field of Search: 178/2C,2D,4.1B,2R,3,4.1R 179/2A,6E,15AL,15BA,15BY,18B,175.2R,175.2C,175.3,175.31R,4,2DP
• US Class Current: 178/2.00C
• CPC Class Codes: H04B 17/406 using coded addresses
• CPC Class Codes: H04M 3/28 Automatic routine testing ; Fault testing; Installation testing; Test methods, test equipment or test arrangements therefor

Abstract

A plurality of remote switching modules are positioned along a telephone communication circuit and are responsive to signals sent by a control unit along the same circuit. The control unit signal includes a plurality of bursts of bipolar digital pulses having a certain format with timed spaces between each burst of pulses. Each remote module counts the pulses received from the control unit through the communications circuit. One of the modules responds when addressed with a burst of pulses of a number for which the module has been uniquely programmed. When a given module has been addressed, another burst of pulses tells the addressed module what switching function to perform.

Claims

1. A method of signaling from a controlling location a predetermined switching function at a remote location along a communication circuit having a transmission bandwidth with a voice range of substantially 300 to 3,000 Hz, comprising the steps of:

initially sending a burst of bipolar pulse pairs along the communication circuit to condition any companders along said circuit for receipt of subsequent pulses, pausing a time that exceeds one repetition period of said initial burst of pulse pairs, sending a of burst of a predetermined number of digital bipolar pulse pairs along said communication circuit from the controlling location, said pulse pairs within the burst all having substantially the same duration, serially counting the number of pulse pairs received at the remote location in time sequence as they are received, performing a predetermined switching function according to the number of pulse pairs counted within said of burst.

2. The method according to claim 1 wherein said pulse pair duration is substantially one millisecond.

3. A method of signaling from a controlling location along a communication circuit a programmed function at a selected one of a plurality of remote locations therealong comprising the steps of:

sending a first address burst of a given number of pulses with a given pulse repetition period along the communication circuit from the controlling location to address a particular remote location, said address burst being preceded and followed by a space characterized by an absence of pulses for time equal to at least two pulse repetition periods, counting the number of pulses of the first address burst within the communication circuit at each of the remote locations, detecting said space after the address burst at each of the remote locations, comparing the first address burst pulse count with a preset unique address at each remote location upon detection of said space, therebY to address a single remote location with a burst of address pulses of a number equal to the reset unique address of said single remote location, sending a function burst of a given number of pulses with said given pulse repetition period along said communication circuit from the controlling location to command the addressed remote location to perform a specific function, said function burst being initiated immediately after said space following the address burst and being followed by another space that is characterized by an absence of pulses for a time equal to at least two pulse repetition periods, counting the number of pulses of said function burst within the communication circuit at the addressed location, detecting said space after the function burst at the addressed location, sending a second address burst of pulses along the communication line after the space following the function burst of pulses, said second address burst having the same number of pulses as the first address burst, counting at the addressed location the number of pulses in said second address burst, and causing execution of a unique programmed function at the addressed remote location in response to the number of pulses counted in the second address burst being equal to the preset unique address of the addressed one remote location.

4. The method of claim 3 wherein said communication circuit includes transmission and reception paths with respect to the controlling location and further wherein said programmed function selected by the number of pulses in the function burst loops the transmission path to the reception path at the addressed location whereby the communication circuit can be tested between the controlling and remote locations from the controlling location.

5. The method of claim 3 wherein said programmed function selected by the number of pulses in the function burst connects a test signal generator into the communication circuit at said remote location.

6. The method according to claim 3 wherein the step of causing execution of a unique function includes providing for testing the quality of the communication circuit between the controlling and remote positions.

7. An apparatus for performing an electrical switching function, comprising, means for setting a unique address of said apparatus, means responsive to an input for emitting a space signal when a pulse has not been received at the input for a set period of time, means responsive to a first burst of pulses at the input and responsive to the space signal for developing a match signal when the number of pulses of said burst equals the preset address coincident with an occurrence of said space signal, means responsive to a second burst of pulses at said input, to said match signal and to the space signal for determining which of a plurality of predetermined switching functions is to be performed by the apparatus, and means responsive to a third burst of pulses at said input and to said space signal for executing the selected predetermined switching function.

8. Apparatus according to claim 7 wherein said means responsive to a third burst of pulses executes the predetermined switching function when the number of pulses of the third burst equals the preset address.

9. A switching module for connection to a communication circuit, comprising, input circuits for connection of the switching module to the communication circuit, a binary counter connected to said input circuits in a manner that the counter increments a given fixed amount for each pulse to be detected in the communication circuit, a binary address code setting means, a comparator circuit monitoring the count of said counter circuit and a fixed binary address code from the binary address code setting means, said comparator emitting a mismatch signal at all times except when the counter is at the same value as the fixed binary address code for the module wherein the comparator emits a Match signal, a space detector connected to said input circuits and having a first output signal when a burst of pulses is being received by the module and a second output signal at the end of the burst of pulses when there have been no pulses for a fixed period of time, and means receiving the space detector output signal and the comparator output signal for changing among first, second, third, and fourth distinct binary states in response to the second output signal being generated by the space detector circuit, the actual change in state being determined by the state of the device upon receiving the second output signal from the space detector and by whether the output signal of the comparator is in a matched or a mismatched state upon receipt of the second output signal from the space detector, whereby said state changing means moves through its distinct binary states in response to the number of pulses in bursts of pulses occurring between spaces.

10. Apparatus according to claim 9 which additionally comprises a word end detector connected to said input circuits and developing an output signal that resets said binaty state changing means to its first state after a fixed period of time after the end of a burst of pulses, said word end fixed period of time being longer than the fixed period of time that said space detector is set to wait before changing to its second output signal level.

11. Apparatus according to claim 9 wherein said binary state changing means moves from its first state to its second state upon the space detector output changing to its second output signal simultaneously with the comparator emitting a match signal.

12. Apparatus according to claim 11 wherein said binary state changing means moves from its second state to its third state upon the space detector output changing to its second output signal simultaneously with the comparator emitting a mismatch signal.

13. Apparatus according to claim 12 wherein said binary state changing means moves from its third state to its fourth state upon the space detector output changing to its second output signal simultaneously with the comparator emitting a match signal.

14. Apparatus according to claim 13 which additionally comprises:

means connected to said counter for temporarily storing the count thereof when said binary state changing means changes from its second to its third state.

15. Apparatus according to claim 14 which additionally comprises means connected to the temporary storage means for permanently storing the counter value as held in the temporary storage when the binary state changing means changes from its third state to its fourth state.

16. Apparatus according to claim 15 which additionally comprises a decoding logic circuit connected to the permanent storage means for converting the counter count stored therein to a single predetermined switching function.

17. Apparatus according to claim 9 which additionally comprises a delay circuit receiving the output signals of the space detector for resetting the counter to zero a short time after the space detector switches from its first output level to its second output level.