Itt Corporation

International Telephone and Telegraph Corporation

John E Cox

Francisco A Middleton

John M Cotton

Franklin Hargrave

Robert Treiber

A data transport system connects with a telephone system for communication of data via subscriber telephone lines to a provider of data services. Connection of multiplexing circuitry to a set of subscriber lines is accomplished at a main distribution frame by adapters or access blocks set between arc suppressors and a terminal block. The multiplexing circuitry is activated by signals of a line scan unit which, in turn, cooperates with a host computer associated with the provider of data services. This arrangement bypasses the central switching equipment. The data may be transmitted out of voice band, if desired, to enable simultaneous voice and data transmission. Passive, active and interactive data can be transmitted by the data transport system.

Information transport system employing telephone lines

In order to reduce hardware cost, apparatus is disclosed for reducing the pin count or terminal count of circuit modules in a large digital system, resulting in condensed packaging and the elimination of huge connecting structures and backplane orientations in such systems. The apparatus depicted employs a time division bus to serially carry data from a plurality of terminal locations and to demultiplex the serial data by means of a demultiplexer to provide a plurality of output logic states on a plurality of parallel data lines. These data lines are directed to a logic array circuit which can perform predetermined logic operations on the data prior to transmission of the same to associated backplanes in the system. The outputs from the logic array circuit are multiplexed to provide a time division serial output bus for transmission to the back planes or shelves of other modules in the system. The entire apparatus as the demultiplexer, the logic array and the multiplexer are preferably contained on the same VLSI chip card or board resulting in a substantial reduction in terminals or pins required for transmission to other system modules.

Apparatus for obtaining reduced pin count packaging and methods

A uniformly manufacturable solid state modular distributed control for a digitally switched local or central office servicing an expandable number of subscribers is disclosed in which subscriber lines and trunks communicate through a standardized hardware interface to a group switch. The described system provides microprocessor control of each call, with software distributed in accordance with the class of service per line, without the limitations of centralized control systems, but expandable without adverse affect on existing software. Switching control signals are communicated to and from the subscriber subsets to the group switch over the same paths which couple the speech signals thereto, thereby eliminating cumbersome and expensive separate control paths. In accordance with a further aspect of the present invention, subscriber calls are divided into orginating and terminating call halves, under subscriber control and separated by the group switch, thereby eliminating undesired interaction therebetween to provide for simplified software requirements.

Growing community of inventors

Stamford, CT, United States of America

John E Cox