Ld Cabling Issues; Wiring To Terminal Devices - Equinox Systems MEGAPORT Hardware Reference Manual

Wiring to Terminal Devices

Complete details about LD ports may be found in Equinox Technical
Note #1, MEGAPORT LD: Exploring Long Distance Connections to
Terminals and Printers, Equinox part number 302024, a copy of
which is enclosed with all MEGAPORT LD boards. This publication
also addresses various other features of the LD products line.

LD Cabling Issues

The long distance capability of the LD interface is due to the high
noise rejection provided by twisted pair cable and the bipolar data
signals used by the LD interface. This interface requires the follow-
ing rules be obeyed in cabling LD ports to devices.
1. It is extremely important that twisted-pair wiring be used
for connecting devices to the ports. To realize the maximum
distance at the highest speed, minimize or avoid the use of
modular flat telephone cable (which does not provide
twisted-pairs).
2. The two input signals: DATA IN(+) and DATA IN(-) must
reside in the same twisted pair. Also, the two output
signals: DATA OUT(+) and DATA OUT(-) must share their
own twisted pair.
Connecting Devices to LD Ports 45