The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Aug. 17, 1982
Filed:
Dec. 08, 1980
Applicant:
Inventor:
Anthony W Sweet, Saffron Walden, GB;
Assignee:
Standard Telephones and Cables Limited, London, GB;
Attorneys:
Primary Examiner:
Int. Cl.
CPC ...
H04M / ; H04Q / ; H04B / ;
U.S. Cl.
CPC ...
179 / ; 179 / ; 179 / ;
Abstract
A telephone subscriber's line interface for a system in which the telephone instrument and the connections therefrom to the exchange use analogue, while the exchange is digital is described, in which electro-mechanical components are eliminated. To achieve this a microprocessor serves a group of lines on a multiplexed basis, responding to conditions of the line as determined via a high impedance monitor and analogue-to-digital conversion means. It also responds to control inputs from the rest of the exchange. In response to the above inputs it controls line feed, signalling, etc. via digital-to-analogue conversion means and a line driver.