scope:

This standard is intended as a base document for the specification and interconnection of packetized circuit multiplication equipment (PCME) and Packet Circuit Multiplication Systems (PCMS) from various manufacturers.

This standard covers the following interface and functional requirements for PCME:

- interface requirements (network-network and user-network), including

- interface with Link Access Procedure DChannel (LAPD);

- interface with DSO-A circuits;

- interface with V.120;

- interface with cellular speech packetization networks and systems;

- signaling interfaces;

- Pulse Code Modulation (PCM)/Adaptive Differential Pulse Code Modulation (ADPCM); code switching for voiceband traffic;

- PCM encoding standards conversion.

- functional requirements, including

- build-out delay, echo control;

- congestion control strategy;

- maintenance and alarm functions;

- testing procedures.

- networking applications requirements, including  

- configurations;

- procedures at intermediate crossconnect nodes, including congestion strategies;

- implementation and applications considerations.

Purpose

PCME converts speech, voiceband data, facsimile, channel-associated (i.e., in-band) signaling, common-channel signaling, video, and digital data information from channelized DSl or Synchronous Optical Network (SONET) formats to LAPD-like frame format. The LAPD-like frames are transported as packet streams in a wideband packet network over a full or fractional DSl, or a SONET virtual tributary.

Wideband packet technology, as used herein, refers to packet systems operating at 1.5 Mbit/s to 150 Mbit/s. To streamline processing and to limit delay so as to accommodate voice, voiceband data, facsimile and video, this technology uses a LAPD-like link layer protocol with unacknowledged operation and applicationspecific layer 3 protocols. Digital data transmission is supported by several layer 3 protocols, as explained in this document.