Data communications network remote test and control system

Abstract

A remote test and control system for use with a data communications network having primary and backup facilities provides full network testing and switching capability from a central location, thereby obviating the need for manual supervision at the remote data terminal stations served by the network.

What is claimed is: 
     
       1. A remote test and control system for use with a data communications network interconnecting a central processing station with at least one remote data terminal station, through a pair of communication links either of which may be selected .Iadd.by a command signal .Iaddend.for passing data information therebetween, with each remote station containing a data terminal and a pair of modems with the data terminal being adapted for connection to the selected communication link through either modem, comprising: command signal transmitter means for generating and transmitting command signals over at least one of the communication links, each command signal being addressed to a selected remote station;   individual command signal receiver means located at each remote station for receiving the command signals addressed to its associated station.Iadd., said receiver means being capable of receiving command signals over whichever link they are transmitted.Iaddend.; and   individual switching means located at each remote station responsive to .[.one.]. .Iadd.a .Iaddend.command signal for connecting the audio terminals and .[.another command signal for connecting the.]. digital terminals of either one of the associated station modems between the selected one of the two communication links and the station data terminal, respectively.   
     
     
       2. The remote test and control system of claim 1 including individual status signal transmitter means located at each remote station for generating and transmitting over at least one of the communication links a status signal indicative of various station conditions following the receipt of a command signal and status signal receiver means for receiving each status signal and displaying the information contained therein. 
     
     
       3. The remote test system of claim 2 including individual modem test means located at each remote station responsive to a command signal for continuously monitoring via its associated individual switching means a selected one of the associated station modems for malfunctions and for providing an indication thereof via a status signal. 
     
     
       4. The remote test system of claim 1 wherein each communication link includes two sections, one for the central station to transmit and the other for it to receive data information and wherein each of said individual switching means is responsive to a command signal for looping a communication link at its associated station by connecting the transmit and receive sections of the communication link together at the station and including an individual test signal generator located at each remote station for connection to the receive section via said individual switching means in response to a command signal for applying to the receive section test signals to measure the line characteristics thereof and test signal generator and analyzer means for receiving and analyzing the test signals over the communication receive section and for also applying test signals to the transmit section. 
     
     
       5. The remote test system of claim 4 wherein each of said individual switching means is responsive to a command signal for placing either of its associated station modems in a digital loop with either one of the two communication links and including digital loop measurement means for applying a digital test signal to the transmit section of the communication link, receiving the transmitted signal over the receive section, and comparing the received signal to the transmitted signal. 
     
     
       6. The remote test system of claim 3 wherein each communication link includes two sections, one for the central station to transmit and the other for it to receive data information and wherein each of said individual switching means is responsive to a command signal for looping a communication link at its associated station by connecting the transmit and receive sections of the communication link together at the station and including an individual test signal generator located at each remote station for connection to the receive station via said individual switching means in response to a command signal for applying to the receive section test signals to measure the line characteristics thereof and test signal generator and analyzer means for receiving and analyzing the test signals over the communications receive section and for also applying test signals to the transmit section. 
     
     
       7. The remote test system of claim 6 wherein each of said individual switching means is responsive to a command signal for placing either of its associated station modems in a digital loop with either one of the two communication links and including digital loop measurement means for applying a digital test signal to the transmit section of the communication link, receiving the transmitted signal over the receive section, and comparing the received signal to the transmitted signal. 
     
     
       8. The remote test system of claim 1 wherein command signals are transmitted over only one communication link and including individual link selector means located at each remote station for detecting that link and connecting thereto its associated station command signal receiver means. 
     
     
       9. The remote test system of claim 3 wherein command signals are transmitted over only one communication link and including individual link selector means located at each remote station for detecting that link and connecting thereto its associated station command signal receiver means. 
     
     
       10. The remote test system of claim 7 wherein command signals are transmitted over only one communication link and including individual link selector means located at each remote station for detecting that link and connecting thereto its associated station command signal receiver means. 
     
     
       11. The remote test and control system of claim 1 wherein the network includes an intermediate processing station containing digital processing means interconnecting either one of the communication links with either one of at least one pair of branch circuits, said processing station including a pair of modems and an individual associated terminal controller for the link pair and for each branch circuit pair with the inputs to all the station terminal controller command demodulation means being connected in common. 
     
     
       12. The remote test and control system of claim 11 wherein the outputs of all the station terminal controller status modulator means are connected in common. 
     
     
       13. A remote test and control system for use with a data communications network interconnecting a central processing station with the data terminal of at least one remote terminal station through a pair of communication links, either of which may be selected .Iadd.by a command signal .Iaddend.for passing data information therebetween, comprising: command signal transmitter means for generating and transmitting command signals over at least one of the communication links, each command signal being addressed to a selected remote station;   individual command signal receiver means located at each remote station for receiving the command signals addressed to its associated station.Iadd., said receiver means being capable of receiving command signals over whichever link they are transmitted.Iaddend.; and   individual switching means located at each remote station responsive to a command signal for connecting the associated station data terminal to the selected one of the communication links.   
     
     
       14. The remote test and control system of claim 13 including individual status signal transmitter means located at each remote station for generating and transmitting over at least one of the communication links a status signal indicative of various station conditions following the receipt of a command signal and status signal receiver means for receiving each status signal and displaying the information contained therein. 
     
     
       15. The remote test and control system of claim 13 wherein each communication link includes two sections, one for the central station to transmit and the other for it to receive data information and wherein each of said individual switching means is responsive to a command signal for looping a communication link at its associated station by connecting the transmit and receive sections of the communication link together at the station and including digital loop measurements means for applying a digital test signal to the transmit section of the communication link, receiving the transmitted signal over the receive section, and comparing the received signal to the transmitted signal.