Combined telephone and data-transfer system
First Claim
1. In a telephone system wherein a multiplicity of subscriber stations communicate with a central office via respective local lines,the combination therewith of:
- a generator of data bits continuously emitted at a location remote from said subscriber stations over a bus common to all said local lines at a high speed exceeding the transmission capacity of said local lines, said data bits being divided into groups each accompanied by an assigned address code;
a multiplicity of retrieval units each connected at said remote location between said bus and a respective local line, each retrieval unit including register means for temporarily storing the bits of any of said groups and reading same out over the associated local line, in response to a request signal from the respective subscriber station identifying such group, at a reduced speed compatible with the transmission capacity of the associated local line; and
display means at each subscriber station connectable to the local line thereof for visualizing the data groups received from the associated retrieval unit.
1 Assignment
0 Petitions
Accused Products
Abstract
Telephone lines extending between a central office and associated subscriber stations are provided at opposite ends with mutually complementary modems and with couplers by which code signals from subscriber-operated address selectors can be sent to a common data network containing specialized information or to associated data-retrieval units. The latter are connected in parallel to a bus originating at a data bank from which data bits grouped into pages are continuously emitted at high speed. Each retrieval unit comprises two shift registers, one of them being loadable from the bus by the incoming high-speed bits to store a complete page together with an accompanying address code while the other receives a selected address code from the associated subscriber. A comparator, upon detecting an identity between the coded addresses stored in the two registers, stops the loading of the first shift register and commands its readout over the subscriber line at a slow rate compatible with that line'"'"'s bandwidth. At the subscriber station the incoming data are displayed on a viewer of a data terminal or, with the aid of an adapter, on a television receiver. The transmission of address codes and other data over any subscriber line occurs between the two modems thereof at frequencies outside the voice band.
130 Citations
7 Claims
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1. In a telephone system wherein a multiplicity of subscriber stations communicate with a central office via respective local lines,
the combination therewith of: -
a generator of data bits continuously emitted at a location remote from said subscriber stations over a bus common to all said local lines at a high speed exceeding the transmission capacity of said local lines, said data bits being divided into groups each accompanied by an assigned address code; a multiplicity of retrieval units each connected at said remote location between said bus and a respective local line, each retrieval unit including register means for temporarily storing the bits of any of said groups and reading same out over the associated local line, in response to a request signal from the respective subscriber station identifying such group, at a reduced speed compatible with the transmission capacity of the associated local line; and display means at each subscriber station connectable to the local line thereof for visualizing the data groups received from the associated retrieval unit. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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Specification