RAD Data comm ASM-20 operation manual Chapter Introduction, Overview, Applications

Chapter 1

Introduction

Applications

H O S T

DTE

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 miles) 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.

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

∙Point-to-point applications (see Figure 1-1)

∙Modem link application (see Figure 1-2)

∙Tail-end for digital networks application (see Figure 1-3).

4 -W IR E

Up to 23 km

R AD R AD

A S M -2 0 19.2 - 256 kbs A S M -2 0

Term inal

Figure 1-1 Point-to-point Application

Overview 1-1