Communication system

A communication system comprising

• a central station and a plurality of remote stations,
• a television program transmitter at said central station for transmitting television signals to all of said remote stations, said television signals including repetitive horizontal synchronizing signals,
• first means for detecting said horizontal synchronizing signals at said transmitter,
• second means at each of said remote stations including a signal transmitter for transmitting information signals to said central station at generally regular but random intervals whereby a relatively large number of remote stations can communicate with a central station without said information signals interfering with each other,
• said second means further including
• a power supply,
• a power pulser comprising switching means for switching power from said power supply to said signal transmitter, and
• a summing amplifier coupled to said power pulser and adapted to be charged to a predetermined voltage level at which it turns on said power pulser, said summing amplifier being coupled to and receiving electrical signals from a sawtooth wave generator, means for extracting said horizontal synchronizing signals, and a random signal generator, and
• third means at said central station for receiving and comparing said horizontal synchronizing signals from said program transmitter with said information signals from said remote stations.

A communication system comprising

• a single central station and a plurality of remote station, said central station being adapted to transmit signals to and receive signals from all of said remote stations, said remote stations transmitting only to said central station but not to any of said remote stations,
• first means at said central station for transmitting the same first signals to all of said remote stations substantially simultaneously,
• each remote station including (1) first means for receiving and selectively utilizing or not utilizing said first signals from said central station and (2) second means for transmitting second signals only to said central station but not to any other of said remote stations, said second signals including information concerning the address of said remote station and information signifying receipt and utilization of said first signals, all of said remote stations, which receive and utilize said first signals, transmitting their second signals to said central station repetitively, and
• second means at said central station for receiving said electrical signal information and registering said signal information for use in a utilization device at said central station.

A communication monitoring system comprising a central station and a pluraity of remote stations and including means forming a communication path from said central station to each remote station and from each remote station to only said central station but to other remote stations,

• each said remote station including (1) a device whose state is to be monitored, the state to be monitored being representable by an electrical signal, (2) a transmitter for transmitting electrical signal information including said signal to said central station, and (3) a source of randomly varying electrical signal,
• said transmitter including means causing it to transmit said electrical signal information repetitively at generally regular but slightly varying intervals only to said central station but not to said remote stations,
• all of the transmitters transmitting said electrical signal information to said central station at generally regular but slightly varying intervals, and
• means at said central station for receiving said electrical signal information and registering said signal information for use in a utilization device at said central station.

A communication system comprising

• a single central station and a plurality of remote stations, said central station being adapted to transmit signals to and receive signals from each remote station,
• first means at said central station for transmitting the same first signals to all of said remote stations,
• each remote station including (1) first means for receiving and selectively utilizing or not utilizing said first signals from said central station and (2) second means for transmitting second signals only to said central station but not to any other remote station, said second signals including information concerning the address of said remote station and information denoting receipt and utilization of said first signals,
• said second means including circuit elements for switching on said second means when said first signals are utilized to transmit a plurality of said second signals at substantially fixed time intervals having small variations in the time that transmission is initiated, the time at which transmission is initiated being determined in part by said first signals, all of said remote stations transmitting their second signals repetitively to said central station, and
• third means at said central station for receiving said second signals and registering said second signals for use in a utilization device at said central station.

A communication system comprising

• a central station and a plurality of remote stations, said central station being adapted to transmit signals to and receive signals from each remote station,
• first means at said central station for transmitting the same first signals to all of said remote stations,
• each remote station including first means for receiving and selectively utilizing or not utilizing said first signals from said central station and second means for transmitting second signals only to said central station, but not to any other remote station, said second signals including information concerning the address of said remote station and information denoting receipt and utilization of said first signals, all of said remote stations transmitting their second signals repetitively to said central station, and
• signal comparing circuitry at said central station for comparing the signals transmitted by said central station with said second signals whereby determination can be made of the remote station which transmitted a second signal.

A communication system comprising

• a single central station and a plurality of remote stations, said central station being adapted to transmit signals to and receive signals from all of said remote stations, said remote stations transmitting only to said central station but not to any of said remote stations,
• first means at said central station for transmitting first signals to all of said remote stations,
• each remote station including first means for receiving said first signals from said central station and second means for transmitting second signals only to said central station but not to said remote stations, said second signals including information concerning the address of said remote station and information signifying receipt of said first signals, and
• second means at said central station for receiving said electrical signal information and registering said signal information for use in a utilization device at said central station, said second means including a transmitter circuit and switching means for switching on said transmitter circuit, said switching means comprising a capacitor, and both a power supply and source of randomly varying signals coupled to and charging said capacitor, said power supply being coupled to and turning on said transmitter when said capacitor is charged to a predetermined voltage level.

A communication system comprising

• a single central station and a plurality of remote stations, said central station being adapted to transmit signals to and receive signals from all of said remote stations, said remote stations transmitting only to said central station but not to any of said remote stations,
• first means at said central station for transmitting first signals to all of said remote stations,
• each remote station including first means for receiving said first signals, from said central station and second means for transmitting second signals only to said central station but not to said remote stations, said second signals including information concerning the address of said remote station and information signifying receipt of said first signals, and
• second means at said central station for receiving said electrical signal information and registering said signal information for use in a utilization device at said central station, said second means including a transmitter circuit and switching means for switching on said transmitter circuit, said switching means comprising a summing circuit to which are coupled a source of a defined ramp signal, a source of a randomly varying signal and a source of defined pulses, said summing circuit operating to switch on said transmitter when the signals received thereby sum to a predetermined level.

A communication system comprising

• a central station and a plurality of remote stations, said central station being adapted to transmit signals to and receive signals from each remote station,
• first means at said central station for transmitting signals to all of said remote stations,
• each remote station including first means for receiving said signals, from said central station and second means for transmitting second signals only to said central station, but not to any other remote station, said second signals including information concerning the address of said remote station and information denoting receipt of said first signals, and
• signal comparing circuitry at said central station for comparing the signals transmitted by said central station with said second signals whereby determination can be made of the remote station which transmitted a second signal,
• said second means including a transmitter circuit and switching means for switching on said transmitter circuit, said switching means comprising a capacitor, and both a power supply and a source of random power are coupled to and charge said capacitor, said power supply being coupled to and turning on said transmitter when said capacitor is charged to a predetermined voltage level.

A communication system comprising

• a central station and a plurality of remote stations, said central station being adapted to transmit signals to and receive signals from each remote station,
• first means at said central station for transmitting signals to all of said remote stations,
• each remote station including first means for receiving said signals, from said central station and second means for transmitting second signals only to said central station, but not to any other remote station, said second signals including information concerning the address of said remote station and information denoting receipt of said first signals, and
• signal comparing circuitry at said central station for comparing the signals transmitted by said central station with said second signals whereby determination can be made of the remote station which transmitted a second signal,
• said second means including a transmitter circuit and switching means for switching on said transmitter circuit, said switching means comprising a summing circuit to which are coupled a source of a defined ramp signal, a source of a randomly-varying signal and a source of defined pulses, said summing circuit operating to switch on said transmitter when the signals received thereby sum to a predetermined level.