Rs-232-c serial interface – AMT Datasouth ACCEL-6300 User Manual

Page 173

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User's Guide

C-8 Interfaces

RS-232-C Serial Interface

The serial interface conforms to the Electronics Industries Association
(EIA) RS-232-C standard for serial communications. This standard
describes a data transfer method between data terminal equipment
(DTE) and data communications equipment (DCE). DTE refers to
computers; DCE refers to modems or other data communications de-
vices. Since the RS-232-C standard does not take printers into account,
manufacturers are free to produce printers that operate as either DTE or
DCE. AMT printers operate as DTE device.

The RS-232-C serial interface contains 25 lines. Only 10 lines carry
signals or are grounded; the remaining 15 lines are not connected.

Voltages

Each line can carry two voltage levels: high and low. Timed high-to-low
and low-to-high transitions on these lines enable the transfer of logical
information. Valid RS-232-C voltage levels are as follows:

9 High (+): +3 to +25 volts

9 Low (-):

-25 to -3 volts

Signals and Data Format

The serial interface consists of eight signal lines and two ground lines:

9 Data Set Ready
9

9 Data Carrier Detect
9

9 Request To Send
9

9 Clear To Send
9

9 Transmit Data
9

9 Receive Data
9

9 Data Terminal Ready
9

9 Inverted Data Terminal Ready
9

9 Chassis and Signal Grounds