Apparatus for interfacing between telecommunications call signals and broadband signals
First Claim
1. In a telecommunications switching system, apparatus comprising:
- means for receiving a plurality of synchronous pulse code modulated (PCM) signals, each signal for carrying a plurality of PCM channels;
means for storing individual bytes of said PCM signals in selectable memory locations of a plurality of buffer memories, each buffer memory for storing a plurality of said bytes; and
means for adding header data to outputs of ones of said buffer memories and for forming a plurality of composite packets, each composite packet comprising bytes from a plurality of PCM channels from a plurality of said PCM signals; and
means for transmitting periodically ones of said plurality of composite packets in output signals to a unit for switching packets of said output signals;
wherein said selectable memory locations are selected to group each of a plurality of bytes of channels destined for a common switching system into one of said composite packets.
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Abstract
In accordance with the principles of this invention, 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 selected from the PCM data streams because they have a common destination. The cells are transmitted over ATM virtual circuits, each circuit transmitting one cell every 125 μs. 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. This application relates to arrangements for converting the PCM signal streams into ATM cells.
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Citations
13 Claims
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1. In a telecommunications switching system, apparatus comprising:
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means for receiving a plurality of synchronous pulse code modulated (PCM) signals, each signal for carrying a plurality of PCM channels; means for storing individual bytes of said PCM signals in selectable memory locations of a plurality of buffer memories, each buffer memory for storing a plurality of said bytes; and means for adding header data to outputs of ones of said buffer memories and for forming a plurality of composite packets, each composite packet comprising bytes from a plurality of PCM channels from a plurality of said PCM signals; and means for transmitting periodically ones of said plurality of composite packets in output signals to a unit for switching packets of said output signals; wherein said selectable memory locations are selected to group each of a plurality of bytes of channels destined for a common switching system into one of said composite packets. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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Specification