초록 ▼

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 demar

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.

대표청구항 ▼

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, respe

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.