Rad-data-comm ASM-20 Manual do Utilizador descarregar pdf (Página 15)

Overview 1-1

Chapter 1

Introduction

1.1 Overview

The ASM-20 short range modem operates synchronously or asynchronously at

full-or half-duplex, over unconditioned lines. ASM-20 has a range of up to 23 km

(14 mi) and operates at selectable data rates from 19.2 kbps to 256 kbps.

ASM-20 uses conditioned diphase modulation (EUROCOM Std. D1) to provide

immunity from background noise, eliminate normal line distortion, and enable

efficient transmission and reception of serial data over a twisted pair cable.

Transmit timing is provided internally, or derived externally from the data terminal

or regenerated from the receive signal.

Receive timing is regenerated from the data.

Applications

The following diagrams illustrate ASM-20 in a variety of applications:

• Point-to-point

• Modem link

• Tail-end for digital networks.

HOST

ASM-20 ASM-20

4-WIRE

Up to 23 km

19.2 - 256 kbs

RAD RAD

DTE

Termina l

Figure 1-1. Point-to-point Application

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