DIGITAL TIME MULTIPLEXED BIDIRECTIONAL COMMUNICATIONS SYSTEM

• US 3,601,806 A
• Filed: 06/23/1969
• Issued: 08/24/1971
• Est. Priority Date: 06/23/1969
• Status: Expired due to Term

• Current Assignee: Gary L. Heimbigner
• Original Assignee: Gary L. Heimbigner
• Inventors: Heimbigner, Gary L.
• Primary Examiner(s): Yusko, Donald J.
• Application Number:
  US04/835,320
• Time in Patent Office: 792 Days
• Field of Search: 178/58,50,4.1 340/147,151,163
• US Class Current: 370/452
• CPC Class Codes: G08C 15/12 the signals being represented by pulse characteristics in transmission link
• CPC Class Codes: H04J 3/08 Intermediate station arrangements, e.g. for branching, for tapping-off
• CPC Class Codes: H04L 12/423 with centralised control, e.g. polling
• CPC Class Codes: H04L 5/16 Half-duplex systems; Simplex/duplex switching; Transmission of break signals non-automatically inverting the direction of transmission

Abstract

Digital signals are bidirectionally transmitted between a master station and a plurality of remote stations on a single wire which serially interconnects all the stations. A connection is provided from the last remote station directly back to the master station. Each station is successively interrogated by means of clock pulses transmitted from the master station, data being transmitted from the master station to the remote station on certain predetermined digital bits established by the clock pulses and data being transmitted from the remote station to the master station on certain other predetermined bits. When the predetermined bit count for each remote station has been completed, this station is deactivated and clock and data pulses are bypassed through this station in either direction to provide communications between the master station and another remote station. This interrogation and bidirectional transmission of data is repeated successively for each remote station until all in turn have been interrogated.

Claims

1. A digital multiplexing system for communicating time multiplexed clock pulses and digital signals comprising, at least one master station, a plurality of remote stations seriaLly connected on a single wire, said master station operable to bidirectionally transmit said clock pulses and digital signals to each of said remote stations sequentially while that station is in an active operating mode, interconnecting means connecting said master station and the first and last of said serially connected remote stations to provide two mutually opposite signal paths for sequential interrogation of said serially connected remote station by said master station, each of said remote stations having an active mode of operation during which said remote station is interrogated by said master station and an inactive mode of operation during which said clock pulses and digital signals are transmitted through said remote stations in either of said mutually opposite directions, each of said remote stations having means for deactivation to said inactive mode of operation when a predetermined bit count for said remote station is completed, said clock pulses and digital signals thereby being bypassed through said remote station in either of said mutually opposite directions, each of said remote stations bypassing said clock pulses and digital signals by switch means wherein said clock pulses and digital signals are regenerated, each of said remote stations further having synchronization means responsive to said master station for resetting said means for deactivation to provide for succeeding cycles of interrogation of said remote station.

2. A remote station for a digital multiplexing system, having an active mode of operation during which digital data and clock pulses are communicated thereby to at least one master station, and an inactive mode of operation during which said data and clock pulses are bypassed therethrough in either of two mutually opposite directions, each of said clock pulses being associated with a predetermined data bit, said remote station comprising a first channel responsive to digital signals received in a first direction from said master station, said first channel operable to provide said digital data and clock pulses for control of functions at said remote station, and a first signal bypass channel associated therewith, a second channel responsive to digital signals received from said master station in a second circuit direction opposite from said first direction, said second channel operable to provide said digital data and clock pulses for control of said functions at said remote station, and a second signal bypass channel associated therewith, said signal bypass channels operable to provide mutually opposite paths to gate said digital data and clock pulses through said remote station when said remote station is in an inactive mode of operation, and said first and second channels are further operable to receive said digital data and clock pulses from said master station and to transmit data back to said master station in the direction from which said digital data and clock pulses are received during said active mode of operation, and said first and second signal bypass channels are operable to bypass said digital data and clock pulses arriving by either of said opposite paths during said inactive mode of operation.

3. In a system for transmitting digital data and a train of clock pulses from a master station to a plurality of remote stations and for transmitting data from each of said remote stations to said master station, each bit of said data being associated with a predetermined clock pulse in said train, said master station and said remote stations being serially interconnected by a single line, said line interconnecting said master station and the first and last of said serially interconnected remote stations for communication therebetween to provide interrogation of said remote stations by said master station in either of two mutually opposite directions, the improvement comprising means in each of said remote stations for successively operating said remote statiOns in an active mode during which data is communicated thereto and therefrom in either of said opposite directions and for operating said stations in an inactive mode during which data and clock pulses arriving at said remote stations from either direction are regenerated and bypassed through said remote station.

4. The system of claim 3 wherein said active mode operating means includes counter means for counting said clock pulses, count decoder means for generating signals in accordance with each predetermined pulse in said train and first means responsive to predetermined signals from said count decoder means for generating data signals for transmission on said line and second means responsive to other predetermined signals from said count decoder means for generating command control signals in response to data arriving from said master station.

5. The system of claim 3 wherein the inactive mode operating means includes direction detector means for detecting the direction in which said clock pulses are arriving, counter means for counting said clock pulses, overflow detector means responsive to said counter means for generating a signal when said counter means has counted all the pulses in said train, switch means for regenerating said data and clock pulses, and logical gating means responsive to said overflow detector means and said direction detector means for activating said switch means to place data and clock pulses arriving at each of said remote stations from one direction on the line running from said stations in a direction opposite to said one direction.

6. A system for transmitting digital data and a train of clock pulses from a master station to a plurality of serially connected remote stations and data from each of said remote stations to said master station by each of two alternative paths, each of said clock pulses being associated with a particular bit of said data, comprising:

said master station operable to bidirectionally transmit digital signals to each of said remote stations for sequential interrogation of each of said remote stations by said master station, interconnection means connecting with a single wire said master station and the first and last of said serially connected remote stations to provide two mutually opposite signal paths for sequential interrogation of said serially connected remote stations by said master station, means in each of said remote stations for receiving said data and clock pulses from said master station and for transmitting data back to said master station in the direction from which said clock pulses are received during an active mode of operation, and means for bypassing data and clock pulses through each of said remote stations during an inactive mode of operation, pulses arriving by one of said alternative paths being bypassed in one direction, pulses arriving by the other of said paths being bypassed in a direction opposite to said one direction.

7. The system of claim 6 wherein said means for bypassing said pulses comprises means for regenerating said pulses in response to the pulses arriving at said remote station.

8. The system of claim 6 wherein said means for transmitting data in the direction from which said clock pulses are received includes direction sensing means for sensing the direction from which said clock pulses are arriving and logical gating means responsive to said direction sensing means for gating said data to said line.

9. The system of claim 6 wherein said means for receiving said clock pulses includes a counter, said counter being adapted to go an overflow condition when all of the pulses in said train have been counted, said inactive mode of operation being initiated and maintained in response to said overflow condition.

10. The system of claim 9 and further including count decoder means responsive to said counter for generating signals indicating the particular digital bit to which said counter has counted, and means for correlating each of said signAls with the bit of data associated therewith.

11. In a system for communicating time multiplexed clock pulses and digital data between a master station and a plurality of remote stations on a single wire, each of said remote stations having an active mode of operation during which data is communicated thereby, and an inactive mode of operating during which data and clock pulses are bypassed therethrough in either direction, the improvement comprising:

means in each of said remote stations for communicating data between said master station and each of said remote stations during an active mode of operation comprising;

counter means for counting the clock pulses, each of said clock pulses being associated with a predetermined data bit, count decoder means for generating output signals in accordance with the count of said counter means, command control means for receiving data signals arriving at said remote station from said master station, signals being fed from said count decoder means to said command control means to time correlate said data signals, data signal source means for generating signals for transmission form said remote station to said master station, said data signal source signals being time correlated with the associated count signals from said count decoder means, said counter means counting through a predetermined number of counts, each of said counts being associated with a particular data bit and then generating a signal indicating an overflow condition, and means for bypassing data and clock signals arriving at said remote station from either direction through said remote station when said counter means indicates overflow during an inactive mode of operation.

12. The system of Claim 11 wherein said bypassing means includes first clock switch means for generating clock pulses for transmission from said remote station in one direction, first data switch means for generating data signals for transmission in said one direction, second clock switch means for generating clock signals for transmission from said remote station in a direction opposite to said one direction, second data switch means for generating data signals for transmission form said remote station in said opposite direction, and gating means for each of said clock switch means and said data switch means, the gating means for the data switch and clock switch means associated with said first direction operating to activate the associated switch means in response to data and clock signals received from the opposite direction, the gating means associated with said clock switch means and said data switch means for the opposite direction operating to activate the associated switch means in response to data signal and clock signals arriving from the first direction, and direction detector means for controlling said gating means.

13. In combination, a master station for generating a train of clock pulses and data signals associated with particular clock pulses in said train and a plurality of remote stations, each of said remote stations operating to generate control functions in response to data signals received from said master station and transmitting data signals back to said master station, each of the data signals from said remote stations being associated with a particular clock pulse of said train, said master station and said remote stations being interconnected by wires forming a closed loop therebetween for communications in either of two directions, each remote station including means for correlating each of said clock pulses with its associated control function, command control means responsive to said correlating means and said data signals for controlling said functions, means for correlating the data signals generated at the remote station with said clock pulses, means responsive to said correlating means for generating data signals associated with each of said clock pulses for transmission to said master station, means for sensing the direction in which clock and data signals are being received at said remote station, counter means for generating an overflow signal when said clock pulse train has completed a cycle, and means responsive to the direction sense detected by said direction detector means and said overflow signal for bypassing clock and data signals arriving at said remote station through said station in the same direction in which they are arriving at said station.

14. The system as recited in claim 13 wherein said bypassing means includes means for regenerating the clock and data signals in response to the clock and data signals received at said remote station.

15. A method for communicating digital data on a single line between a master station and a plurality of remote stations, each bit of said digital data being associated with a predetermined pulse of a clock pulse train transmitted by said master station comprising the steps of transmitting a clock pulse train and data from said master station to each of said remote stations successively in a first order, correlating each of the data signals with its associated clock pulse at the remote station and performing a predetermined control function in response thereto, generating data signals at each remote station in response to clock pulses associated therewith, transmitting said data signals to said master station when all of the clock pulses in the train have been received by a remote station bypassing clock pulses and data received at said station from either direction through said station, and when the clock pulse train has been successively transmitted to said remote stations in said first order, successively transmitting said pulse train to said remote stations in an order opposite said first order.

16. The method of Claim 15 wherein the bypassing of said clock pulses and data includes the regenerating of said pulses and data at each of said remote stations in response to data and clock pulses received thereby. 17 A remote station for a digital multiplexing system comprising:

direction detector means for detecting from which of two mutually opposite directions clock pulses are arriving from a master station, counter means for counting said clock pulses, count decoder means for generating signals in response to predetermined ones of said clock pulses, data signal source means responsive to predetermined signals from said count decoder means for generating data signals for transmission to said master station, data switch means responsive to said data signal source means for transmission of data signals back to said master station, command control means responsive to other predetermined signals from said count decoder means for generating signals for control of said remote station functions, overflow detector means responsive to said counter means for generating a signal when said counter means has counted a predetermined number of clock pulses, switch means responsive to said overflow detector for regenerating and bypassing digital data and clock pulses received by said remote station in either of said mutually opposite directions, and synchronization means responsive to said master station operable to reset said overflow detector means and said count decoder means to provide for succeeding cycles of interrogation of said remote station.