Chapter 2. TECHNICAL PRINCIPLES OF OPERATION

TM 11-7025-233-23

CHAPTER 2

TECHNICAL PRINCIPLES OF OPERATION

2-1. GENERAL

This chapter tells how the teleprinter works. This information will help during

It will also make maintenance tasks easier.

troubleshooting.

2-2. FUNCTIONAL DESCRIPTION

The teleprinter is a receive or read-only device. It operates under control of a

host system such as a computer to print information directed to it. It can send

status signals to the host system, but it cannot transmit any data to it.

It is an electromechanical device. It is electrically powered and electronically

controlled by circuits on printed circuit boards. Paper movement and all printing

operations, however, are by mechanical devices.

2-3. LOGIC BOARD

The logic board operates and controls the teleprinter. It receives and processes

commands and data from the system to which it is connected and sends data on its

own status back to the system. Its functions include distributing and controlling

power to all electrically operated teleprinter components. It also provides the

signals to print characters, to move the ribbon, to move the carriage, and to

advance the paper. It also stores its own self-test programs. This board includes

the following circuits and components:

q Clock

oscillator driver for servo control circuits

q Driver

for logic circuits

q Program

interval timer and a ribbon drive motor timer

q Control

logic for the carriage drive and paper feed servomotors

q Print

head drive circuits

q Character

q Logic

for the print position indicator (PPI) and the control panel

q ROM

and RAM

q Two

q Audio

transducer (speaker)

2-1