Method and apparatus for confirming transmission in bidirectional CATV system

• US 4,156,847 A
• Filed: 04/14/1977
• Issued: 05/29/1979
• Est. Priority Date: 04/16/1976
• Status: Expired due to Term

• Current Assignee: Pioneer Electronics (USA) Incorporated (Pioneer Corporation)
• Original Assignee: Pioneer Electronics (USA) Incorporated (Pioneer Corporation)
• Inventors: Tazawa, Osamu, Tsuda, Youichiro
• Primary Examiner(s): Griffin, Robert L.
• Assistant Examiner(s): Chin, Tommy P.
• Application Number:
  US05/787,708
• Time in Patent Office: 775 Days
• Field of Search: 325/31, 325/53, 325/308, 325/30, 325/309, 325/390-394, 358/84, 358/86
• US Class Current: 725/107
• CPC Class Codes: H04H 20/12 Arrangements for observation, testing or troubleshooting
• CPC Class Codes: H04H 20/76 Wired systems
• CPC Class Codes: H04H 20/79 using downlink of the CATV systems, e.g. audio broadcast via CATV network
• CPC Class Codes: H04H 60/97 using uplink of the CATV systems
• CPC Class Codes: H04L 5/02 Channels characterised by the type of signal

Abstract

In a bidirectional CATV system, in which interrogations and commands to terminals for individual subscribers occur at high speed, the status of individual terminals is checked rapidly and reliably without interfering with other transmissions. In response to diagnostic commands from the head end unit, the terminal responds with a message that is unlike the usual transmission, and identifies the status established in response to prior commands. The head end unit is thereby without delay able to ascertain not only that the prior commands were correctly transmitted and received but that the appropriate actions were taken in response thereto.

Claims

1. Apparatus for confirming transmission in a bidirectional CATV system which comprises a terminal unit including receiving means for receiving downstream signals include a command data from a head end, demodulating means for demodulating the downstream signals received by said receiving means to derive demodulated data, a control means for controlling the terminal unit in response to the demodulated data, detecting means responsive to said control means for detecting the state of the terminal unit to convert it to status data, memory means for storing said command data demodulated by said demodulating means and said status data as to the response of the terminal unit to said a command, upstream signal transmitting means for transmitting the status data from said detecting means to the head end, data selecting means responsive to a signal from said demodulating means when a diagnostic command is fed from the head end to feed out the status data stored in said memory means through said transmitting means to the head end while terminating data as to the state of the terminal unit, and comparing means at said head end for comparing whether the status data stored in said memory means is consistent with a prior command transmitted from the head end or not when the status data stored in said memory means is transmitted to the head end in response to said diagnostic command to confirm whether the data transmitted from the head end was previously accurately received and responded to in the terminal unit or not.

2. Apparatus according to claim 1, further comprising means coupled to said receiving means and said transmitting means for converting the data signal in the downstream and upstream signals to bi-phase space (BPS) signal to transmit and receive the data signal.

3. A terminal unit in a bidirectional CATV system which comprises a receiving circuit for receiving a downstream common signal from a head end, a demodulating circuit for demodulating the downstream command signal received by said receiving circuit to derive a demodulated command data, a memory circuit for storing the demodulated command data and data as to the status of the terminal unit in response to a command, a control circuit for controlling said terminal unit in response to the demodulated command data, a detecting circuit coupled to said control circuit for detecting the state of said terminal unit to convert it to said status data, an upstream signal transmitting circuit for transmitting the status data from said detecting circuit to the head end, and a data selecting circuit coupled to said memory circuit and responsive to a diagnostic command supplied from the head end, the data selecting circuit being coupled to substitute the status data from said memory circuit for the data from said detecting circuit for passage through said transmitting circuit to the head end.

4. A method for confirming transmission in a bidirectional CATV system which comprises terminal units in communication with a head end unit, said method comprising the steps of:

receiving downstream signals from the head end;

demodulating the received downstream signals to derive command data;

controlling the terminal unit in response to the demodulated data;

assembling upstream data messages as to the status of the terminal unit;

storing the demodulated command data and status data as to actions undertaken by the terminal unit in response to said command data;

identifying diagnostic commands from the head end;

selecting the responsive status data from the stored data for transmission in place of assembled message data when a diagnostic command is detected;

transmitting the selected message upstream to the head end; and

comparing the data received in response to the diagnostic command at the head end to determine whether the stored responsive status data is consistent with the prior command transmitted from the head end, to confirm whether the data transmitted from the head end was previously accurately received and responded to in the terminal unit or not.