Chapter 2 OPERATING INSTRUCTIONS

TM 11-7440-232-12/NAVELEX 0967-LP-275-5010

CHAPTER 2

OPERATING INSTRUCTIONS

Section I. DESCRIPTION AND USE OF OPERATOR'S CONTROLS AND INDICATORS

2-1. GENERAL

a. As the operator of the digital data modem, you will be concerned with four types of controls and two indicators.

CONTROLS

INDICATORS

Transmit And Receive Mode

Power

Bit Rate

Errors

Alarm

Power Supply

b. Location of operating controls and indicators on modules is shown on a decal on the inside of the Modem shelf

front cover.

2-2. CONTROLS

TRANS MODE Switch

· Five position rotary switch

· During operation, switch position NORM allows

transmission of input digital data.

· During organizational maintenance and testing:

LOW-1200 Hz signal is applied to transmit line

HIGH-2400 Hz signal is applied to transmit line

REV-test pattern generator produces a reversal

pattern of alternate ones and zeroes; and signal

appearing on transmit line resembles alternate

one and zero data input pattern for particular

data rate applied.

PATT-test pattern generator produces a random

data input which results in a random data output

on transmission line.

BIT RATE Switch

· Two position rotary switch

· During operation controls transmitted data rate

LOW-600/1200 bps

HIGH-2400 bps

LIMITER DISCRIMINATOR

REC MODE SWITCH

· Two position rotary switch

· During operation switch position allows reception

of received digital data

2-1