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CHAPTER 2: Introduction
2. Introduction
2.2 Features
• Extends parallel communication
to 2000 feet (609.6 m)
• Requires no AC power or
batteries
• Operates over a single twisted
pair
• Allows devices to communicate
in “real time”
• Can be configured for BUSY or
ACKNOWLEDGE flow-control
methods
• Compatible with most printer-
sharing devices
• Transmits DC power over the
line to compensate for low-
power parallel-printer interfaces
• DB25 or Centronics parallel
connections
• RJ-11 or terminal-block line
connections
2.1 Description
The Parallel Line Driver allows
a PC and a parallel output device
(printer, sharing switch, etc.) to
communicate at distances to
2000 feet (609.6 m) over a single
unconditioned twisted pair.
Supporting parallel data rates to
5 kilobytes per second (serial rates
to 40 kbps), the Parallel Line Driver
derives all necessary operating power
from the parallel interface—no AC
power or batteries are required.
The Parallel Line Driver always
works in pairs: A transmitter unit is
plugged into the PC’s parallel port,
and a receiver unit is plugged into
the output device’s parallel port.
The connection between them is
serial, and functions at speeds high
enough to allow real-time parallel
communication between the two
parallel devices.
The Parallel Line Driver has
two unique features that allow it to
operate in a wide variety of parallel
applications: First, the Line Driver
transmitter is able to send DC power
down the line to the receiver in
order to compensate for low power
parallel printer interfaces. Second,
the Parallel Line Driver can be
configured for either BUSY or
ACKNOWLEDGE flow-control
methods.
The Line Driver receiver is
available with Centronics
®
parallel
interface. The Line Driver trans-
mitter is available with a DB25
parallel interface. Line-connection
options are RJ-11 or terminal block
with strain relief.