Digital communication system for transmitting digital information between a central station and a number of remote stations

A communication system for transferring digital information from at least one remote station to a central station, said communication system comprising:

• a signal source coupled to said remote and central stations;
• reference means connected to said signal source in said remote and central stations for generating the same time reference pulse signal in said remote and central stations from the signal provided by said signal source;
• counter means located in each of said remote and central stations for storing digital information by counting the pulses in the time reference pulse signal;
• signal transmitting means connected to said counter means in each of said remote stations for transmitting marking signals to said central station indicating the starting and stopping of said counter means in each of said remote stations;
• signal receiving means connected to said counter means in said central station for receiving the marking signals and supplying the marking signals to said counter means in said central station to start and stop said counter means in said central station in synchronization with the starting and stopping of said counter means in said remote station to thereby transfer
• digital information from said counter means in at least one remote station to said counter means in said central station.

A communication system for transferring digital information from a central station to at least one remote station and vice versa, said communication system comprising:

• a signal source coupled to said remote and central stations;
• reference means connected to said signal source in said remote and central stations for generating the same time reference pulse signal in said remote and central stations from the signal provided by said signal source;
• counter means located in each of said remote and central stations for storing digital information by counting the pulses in the time reference pulse signal;
• selection means located in said central station for selecting a particular one of said remote stations for operation according to a preassigned address and storing the selected address in said counter means in said central station;
• signal transmitting means connected to said counter means in said central station for transmitting marking signals to said remote station indicating the starting and stopping of said counter means in said central station;
• signal receiving means connected to said counter means in said particular one of said remote stations for receiving the marking signals and supplying the marking signals to said counter means in said particular one of said remote stations to start and stop said counter means in synchronization with the starting and stopping of said counter means in said central station to thereby transfer the selected address from said counter means in said central station to said counter means in said remote station;
• comparing means located in each of said remote stations for comparing the selected address in said counter means in said remote station with the preassigned address of said remote station, said comparing means being responsive to a match between the preassigned address and the selected address to enable said remote station to transmit digital information to said central station.

A communication system for transmitting digital information from a remote station to a central station comprising:

• a signal source coupled to said remote and central stations;
• reference means connected to said signal source in said remote and central stations for generating the same time reference pulse signal in said remote and central stations from the signal provided by said signal source;
• down counter means located in said remote station for storing said digital information;
• up counter means located in said central station for receiving said digital information transmitted from said remote station;
• start means connected to said down counter means for generating a start signal in said remote station for enabling said down counter means to count down to zero by counting the pulses in the time reference pulse signal, said down counter means generating a stop signal when said down counter means reaches zero;
• transmitting means located in said remote station for transmitting said start and stop signals to said up counter means in said central station, said up counter means being enabled by said start and stop signals to up count by counting the pulses in the time reference pulse signal to thereby store the same digital information previously stored in said down counter means in said remote station.

A bidirectional digital communication system for a power distribution system having a central station and a plurality of remote stations, said communication system comprising:

• a signal source formed by the 60 Hz power lines of the power distribution system coupled to said central and remote stations;
• reference means connected to said signal source in each of said stations for generating the same time reference pulse signal in each of said stations;
• request means in said central station for generating a request signal indicative of the selected address of a particular remote station, said request means including address down counter means for storing the selected address of said particular remote station and logic means for actuating said down counter means in synchronization with the time reference pulse signal to thereby generate a marking signal which identifies the starting and stopping of said down counter means;
• transmitting means in said central station for transmitting the marking signal to said remote stations by radio waves;
• receiving means in each of said remote stations for receiving the marking signal transmitted by said central station;
• and
• address comparison means in each of said remote stations for comparing the selected address with the preassigned address of said remote station and generating a match signal when the selected address matches the preassigned address of said remote station, said address comparison means including address up counter means and logic means for actuating said address up counter means in synchronization with the time reference pulse signal, said logic means being responsive to the marking signal to start and stop said address up counter means in the same time interval as said address down counter means in said central station to thereby transmit the address stored in said address down counter means in said central station to said address up counter means in said remote station, said address comparison means further including a comparator means controlled by said logic means for comparing the address stored in said address up counter means to the preassigned address of said remote station.

A method for transmitting digital information from at least one remote station to a central station and vice versa, said remote station including first counter means for storing said digital information and said central station including second counter means, said method comprising the steps of:

• generating the same time reference signal in said remote and central stations;
• synchronizing the operation of said first and second counter means by using the same time reference signal in said first and second counter means as a counting input;
• starting the counting of said first counter means in said remote station;
• transmitting a first marking signal from said remote station to said central station to indicate the initiation of counting in said first counter means;
• applying said first marking signal to said second counter means in said central station to initiate the counting in said second counter means;
• stopping the counting of said first counter means in said remote station;
• transmitting a second marking signal from said remote station to said central station to indicate the termination of counting in said first counter means;
• applying said second marking signal to said second counter means in said central station to terminate the counting in said second counter means to thereby transmit digital information stored in said first counter means to said second counter means.

A method for transmitting digital information from a remote station to a central station and vice versa comprising the steps of:

• generating the same time reference pulse signal in said remote and central stations;
• storing digital information in down counter means located in said remote station;
• clearing an up counter means located in said central station in preparation for receipt of the digital information;
• synchronizing the operation of said down counter means and said up counter means by using the time reference pulse signal as a counting input for both said down counter means and said up counter means;
• generating a start signal in said remote station for starting said down counter means in said remote station;
• transmitting the start signal to said central station to start said up counter means in said central station;
• generating a stop signal in said remote station when said down counter means reaches zero;
• transmitting the stop signal to said central station for stopping said up counter means in said central station to thereby transmit digital information from said down counter means in said remote station to said up counter means in said central station by starting and stopping both said counter means within the same relative time interval.