Bi-directional data transmission and control system

• US 4,343,042 A
• Filed: 07/09/1979
• Issued: 08/03/1982
• Est. Priority Date: 07/10/1979
• Status: Expired due to Term

• Current Assignee: Moore Diversified Products, Inc.
• Original Assignee: Cablebus Systems Corporation
• Inventors: Gumm, Linley F., Schrock, Clifford B.
• Primary Examiner(s): Chin, Tommy P.
• Application Number:
  US06/056,283
• Time in Patent Office: 1,121 Days
• Field of Search: 455/3, 455/4, 455/5, 455/6, 455/2, 455/348, 455/349, 364/900, 358/84, 358/86, 358/114, 358/117
• US Class Current: 725/116
• CPC Class Codes: H04L 12/2801 Broadband local area networks
• CPC Class Codes: H04N 2007/17372 the upstream transmission being initiated or timed by a signal from upstream of the user terminal
• CPC Class Codes: H04N 7/173 with two-way working, e.g. subscriber sending a programme selection signal

Abstract

A bi-directional data transmission and control system utilizing a central processing unit and a multiplicity of remote subscribers. Each subscriber is provided with a terminal coupled with the central processing unit by a suitable medium such as a CATV channel. Each terminal is provided with a demarcation plane separating common circuitry from a number of specialty modules and a common bus therebetween for circuitry simplification, application expandability and individual tailoring. The data transmission scheme efficiently utilizes the frequency spectrum and enhances polling frequency by permitting selective polling of any given specialty module or subscriber at any given time and by permitting simultaneous polling of every subscriber for service calls, thereafter locating the caller with minimal polling. Data transmission protocol is expandable or contractable for each terminal independently of others and permits data transmission between any two points in the system. The system is zoned such that failure of one zone does not disable the entire system.

Claims

1. In a bi-directional data transmission system including a cable television (CATV) headend, said headend including a centrally-located computer for monitoring and controlling multiple different remote service devices at each of a multiplicity of subscriber terminals coupled to said CATV headend, respective circuit means different from one another for interfacing each of said remote service devices with a respective one of said terminals, and transceiver means for sending and receiving serial message packets bi-directionally between said CATV headend and said terminals, the improvement comprising:

(a) demarcation means at each of said terminals operatively interposed between said CATV headend and said respective circuit means, said demarcation means including means for converting messages between parallel and serial formats respectively and including first data bus connecting means for initiating a data bus having multiple lines for conducting messages in said parallel format; and

(b) respective modules, each containing a respective one of said circuit means and each having a pair of data bus connecting means for detachably connecting a first one of said modules to said first data bus connecting means and detachably connecting said modules consecutively to each other, and for continuing said data bus consecutively through each module from one to another thereof such that messages can be transmitted on said data bus consecutively through each module without alteration thereof by said modules.

4. The system recited in claim 1, 2 or 3 further including means for testing each of said respective circuit means by comparing a computer-initiated message packet with the response of said respective circuit means to said computer-initiated message packet.

5. The system recited in claim 1, 2 or 3 wherein said transceiver means includes respective transmitting and receiving portions at each of said terminals and frequency control means at each of said terminals having an oscillator common to both said transmitting and receiving portions respectively for operating said transmitting and receiving portions respectively at two different frequencies.

2. In a bi-directional data transmission system including a cable television (CATV) headend, said headend including a centrally-located computer for monitoring and controlling multiple different remote service devices at each of a multiplicity of subscriber terminals coupled to said CATV headend, respective circuit means different from one another for interfacing each of said remote service devices with a respective one of said terminals, and transceiver means for sending and receiving serial message packets bi-directionally between said CATV headend and said terminals, the improvement comprising:

(a) a data bus having multiple lines at each of said terminals;

(d) data bus connecting means on each of said respective circuit means for detachably connecting multiple ones of said respective circuit means simultaneously to said data bus;

(c) demarcation means at each of said terminals operatively interposed between said CATV headend and said data bus, said demarcation means including means for converting messages between parallel and serial formats respectively;

(d) said demarcation means further including microprocessor means for varying the length of said serial message packets transmitted from the respective terminal to said CATV headend in response to the amount of data contained therein.

3. In a bi-directional data transmission system including a cable television (CATV) headend, said headend including a centrally-located computer for monitoring and controlling multiple different remote service devices at each of a multiplicity of subscriber terminals coupled to said CATV headend, respective circuit means different from one another for interfacing each of said remote service devices with a respective one of said terminals, and transceiver means for sending and receiving serial message packets bi-directionally between said CATV headend and said terminals, the improvement comprising:

(a) a data bus at each of said terminals having a multiplicity of sub-address lines and a further line separate from said multiplicity of sub-address lines;

(b) data bus connecting means on each of said respective circuit means for detachably connecting multiple ones of said respective circuit means simultaneously to said data bus;

(c) said CATV headend including means for transmitting simple sub-address data to said terminals in serial message packets of a first length, and means for transmitting complex sub-address data to said terminals in serial message packets of a length greater than said first length;

(d) demarcation means at each of said terminals operatively interposed between said CATV headend and said data bus for converting said serial message packets containing sub-address data to a parallel format;

(e) said demarcation means further including microprocessor means for selectively directing said simple sub-address data through less than all of said multiplicity of sub-address lines while activating said further line of said data bus in response to the transmission of said simple sub-address data from said CATV headend, and including means for selectively directing said complex sub-address data through said multiplicity of sub-address lines in response to the transmission of said complex sub-address data from said CATV headend.