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:
Jun. 27, 1995
Filed:
Dec. 20, 1993
Thomas L Hiller, Glen Ellyn, IL (US);
Ronald A Spanke, Wheaton, IL (US);
John J Stanaway, Jr, Wheaton, IL (US);
Alex L Wierzbicki, Bolingbrook, IL (US);
Meyer J Zola, Oak Park, IL (US);
AT&T Corp., Murray Hill, NJ (US);
Abstract
Pulse Code Modulation (PCM) signal streams are converted into Asynchronous Transfer Mode (ATM) cells for switching and transmission across a telecommunications network. Each cell carries one PCM sample of up to 48 different voice connections, the voice connections being selected from the PCM data streams because they have a common destination. The cells are transmitted over ATM virtual paths, each path transmitting one cell every 125 .mu.s. The ATM signals are switched by units for switching cells (cell switching), while keeping their payload contents intact, and by units for switching the signals for individual voice connections between cells of an ATM signal (cell remapping). Advantageously, ATM transmission systems interface with PCM systems without adding appreciable delay and without requiring additional buffering. Advantageously, new voice paths can be established most of the time by using available slots in the cells of existing virtual paths. Advantageously, large telecommunication networks can be implemented using a small number of switching units. For use with PCM switches, it is desirable to provide supervisory signals accompanying the PCM data. Advantageously, this arrangement permits supervisory signals to be passed within an access switch thus simplifying compatibility with existing switching systems.