Chapter 2 TECHNICAL PRINCIPLES OF OPERATION

TM 11-7025-234-23

CHAPTER 2

TECHNICAL PRINCIPLES OF OPERATION

This chapter explains how the V.29 modem works., and how it interfaces with

transmission lines to send and receive data.

2-2. OPERATING PRINCIPLES

The V.29 modem normally operates unattended except for normal monitoring of

indicator lamps. Each local and remote modem is automatically synchronized if

output rate quality degrades during operation. The input and output data rate is

normally 9600 bps. It is possible for the unit to switch down automatically to a

lower rate if degradation does occur. Start up is accomplished by the operator

using controls on the front panel.

2-3. CONTROLS AND INDICATORS

All operating controls and indicators are accessible from the front of the modem

(fig. 2-1). Access to mode and rate controls, status indicators, and diagnostic

test switches is obtained by lowering the front panel.

a. Mother Board Controls. The mother board controls and indicators are located

at the bottom of the front panel and are shown and described in figure 2-2.

b. Front Panel Controls and Indicators. The controls and indicators for the

different boards are found on the edqes of the boards and protrude through slotted

locations on the front panel (fig. 2-3).

Front Panel

2-1