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:
Sep. 06, 1977
Filed:
Jun. 24, 1976
Thomas Henry Daugherty, Succasunna, NJ (US);
Dale Eugene Stone, Cedar Knolls, NJ (US);
Bell Telephone Laboratories, Incorporated, Murray Hill, NJ (US);
Abstract
A digital subscriber loop transmission system is disclosed through which a number of remote subscribers are serviced with a smaller number of time division channels. The digital transmission system includes an automatic channel testing unit which selects digital channels one at a time and in sequence for a series of automatic tests. Channels which fail these tests are withdrawn from service. One such test involves ringing and automatic number identification circuits by means of which subscribers' telephones are rung and the off-hook subscriber on a two-party line is identified, both by the use of supervisory codes in the digital pulse stream. These supervisory codes are used to test the supervisory circuits themselves and, incidentally, large portions of the overall system.