RAD Data Communications 146 User Manual

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146

RAD Data Communications

2006 Catalog

Miniature short range modems offer the

same communications functions as AC-

powered modems but with fewer features,

such as limited diagnostics capability and no

BER tests. Usually they operate over shorter

distances at lower rates (normally up to

19.2 kbps). However, certain modems can

operate at data rates up to 115.2 kbps in

async transmission and up to 128 kbps in

sync transmission. Like AC-powered

modems, miniature modems are designed

to overcome distance limitations of standard

data communications interfaces such as

V.24/RS-232. They also overcome noisy

environments and provide ground isolation.

Miniature short range modems connect

computers, terminals, bridges/routers and

similar data communications devices inside

buildings, campuses or within city

boundaries. They support simple point-to-

point communications as well as complex

multipoint campus-wide systems. They also

support flow control when connected to a

printer or a multiplexer.

Typical communications problems, such as

distance limitations and noise, are overcome

by using special signal modulation and line

equalization techniques that allow for

error-free transmission over longer

distances. RAD miniature modems have

transformers to isolate the equipment from

the line and ensure safety. The transformers

are rated at over 1,500 VRMS and are

approved by carriers worldwide for

connection to their lines.

What is the difference between

interface-powered and AC-powered

modems?

Interface-powered and AC-powered

modems perform the same basic

communications functions. Interface-

powered modems incorporate innovative

VLSI and hybrid circuitry that enable them to

consume very little power. These modems

draw power from the interface signals

without loading the adjacent equipment or

interfering with normal operation. For

computers that do not support control

signals, there are special models that derive

their power solely from the data signals.

How do you select the right modem for

your application?

Several factors should be considered when

selecting a modem:

• Computer/DTE interface: V.24/RS-232,

V.35, etc.

• Communication method: sync, async or

both

• Data rate

• Distance

• Media: twisted pair, coax, fiber

• Point-to-point or multipoint application

• Control signals (does the application

require transmission of data only, or also

transmission of one or more control

signals?)

• Environment (is the environment noisy?)

A Quick Reference Guide on pages 158-159

will help you select the most suitable

modem for your application.

Miniature short range modems

offer a simple, low cost and highly

reliable method to connect digital

devices in a local, campus or

metropolitan environment. They

also offer very easy installation

since in many cases they do not

require AC power, but derive their

power from the interface signals.

Miniature Modems

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Summary of 146

Page 1
12 146 rad data communications 2006 catalog miniature short range modems offer the same communications functions as ac- powered modems but with fewer features, such as limited diagnostics capability and no ber tests. Usually they operate over shorter distances at lower rates (normally up to 19.2 kbp...
Page 2: Cmn-16
M i n i a t u r e s h o r t r a n g e m o d e m s 147 rad data communications 2006 catalog 12 m inia tur e shor t r ang e m ode m s cmn-16 compact modem nest the following cards are available: cmn-c6a – dual async short range modem card, compatible with srm-5a, srm-6a, srm-3a cmn-c6ac – dual async m...
Page 3: Srm-31S
148 rad data communications 2006 catalog m i n i a t u r e s h o r t r a n g e m o d e m s srm-31s miniature multirate 2-wire modem the srm-31s miniature synchronous modem operates full duplex over a single pair of wires. It supports data rates from 1.2 kbps to 128 kbps. The transmission range is up...
Page 4: Srm-5Ac, Srm-6Ac
M i n i a t u r e s h o r t r a n g e m o d e m s 149 rad data communications 2006 catalog 12 m inia tur e shor t r ang e m ode m s srm-5ac, srm-6ac asynchronous multipoint short range modems the miniature srm-5ac and srm-6ac are short range modems connecting full or half duplex asynchronous termina...
Page 5: Srm-5S
150 rad data communications 2006 catalog m i n i a t u r e s h o r t r a n g e m o d e m s srm-5s synchronous short range modem the miniature srm-5s is a short range modem connecting full duplex synchronous terminals, controllers and computers. It operates at nine data rates up to 19.2 kbps. When op...
Page 6: Fom-485
151 rad data communications 2006 catalog m i n i a t u r e s h o r t r a n g e m o d e m s / m i n i a t u r e f i b e r 0 p t i c m o d e m s 12 m inia tur e shor t r ang e m ode m s / m inia tur e fiber 0ptic m ode m s fom-485 miniature rs-485 fiber optic modem the fom-485 is an asynchronous minia...
Page 7: Fom-9
152 rad data communications 2006 catalog m i n i a t u r e f i b e r o p t i c m o d e m s fom-9 sync/async high speed fiber optic modem the fom-9 is a miniature sync/async fiber optic modem operating full or half duplex over fiber optic cable. It has a range of 15 km (9 miles) over single mode fibe...
Page 8: Fom-8
M i n i a t u r e f i b e r o p t i c m o d e m s 153 rad data communications 2006 catalog 12 m inia tur e fiber optic m ode m s fom-8 fom-8 fiber optic cable fom-8 sync/async fiber optic modem visit www.Rad.Com for latest product updates • selectable sync or async operation • v.54 diagnostics • sel...
Page 9: Fom-6Av
154 rad data communications 2006 catalog m i n i a t u r e f i b e r o p t i c m o d e m s fom-6av high speed fiber optic modem transmission over fiber ensures data integrity, high immunity against emi/rfi and data security. The modem supports ranges of up to 3 km (1.9 miles) over multimode fiber an...
Page 10: Mme, Mme/v.35
155 rad data communications 2006 catalog m o d e m e l i m i n a t o r s 12 m inia tur e fiber optic m ode m s / m ode m eli m ina t o r s mme, mme/v.35 replaces two sync modems of 100 m (330 ft) on each side. Mme operates at selectable data rates up to 19.2 kbps. Mme/v.35 operates at 56/64 kbps, re...