AUDIOLINE POWER PMR 40 Manual de usuario descargar pdf (Pagina 5)

A.W. Communication Systems Limited

TRip2 Manual, Version 1.5 Page 5 of 34 © AWCSL 2010

1. References

1) RFC3550 – RTP: A Transport Protocol for Real-Time Applications [July 1003]

2) draft-eitf-avt-profile – RTP Profile for Audio and Video Conferences with Minimal Control

[March 2003]

2. Scope

This document describes the TRip2, a gateway suitable for interfacing the following over a

10/100 Mbps Ethernet LAN:

 Four-wire analogue circuits,

 RS-232 serial data, and

 9 active-low logic levels, including one PTT logic circuit.

The TRip2 replaces for the original TRip unit, which is now obsolete. TRip2 units are compatible with

original TRip2 units, as long as the audio codec used is not changed from its default setting of

64 kbits/s (G.711 A-law compression). In addition, the physical interface to the TRip2 is identical with

that of the original TRip unit, with the exception that the internal pull-ups on the logic pins are now

referenced to +3.3 V, not +5 V as in the original TRip.

3. Introduction

For historic reasons the PMR (private mobile radio) market has often used four-wire analogue

circuits provided by the local telecoms provider to carry audio between operators and remotely

situated transmitters.

The increasing availability of low-cost “always-on” IP connections has raised the possibility that

these links can be replaced using a packet-based connection, rather than the direct physical

connection provided by the older four-wire analogue circuits.

The TRip2 is specifically designed to satisfy the requirements of the industry for a device that can

interface between existing operator/transmitter switch equipment that has a four-wire audio

interface and an IP network capable of carrying the audio traffic packet data.

This document will describe the form, features and functionality of a standalone TRip2 unit.

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