Introduction - Black Box 37687 User Manual

Introduction

The following guide describes pinouts and cables for the Terminal Server (DB25), Rack
Terminal Server(RJ45) and 102/104 Terminal Server (RJ45) units. Both versions equipped
with RJ45 connectors are also available as RS-422 units.
Any cable you use should be shielded to comply with FCC requirements. Be careful not to
run data cables near fluorescent lights, electric motors or other sources of electrical noise.
Maximum cable lengths for RS-232 are specified at 60m (200 feet) but are proportional to
baud rates - the higher the baud, the smaller the cable should be. A good rule of thumb is
that a 19200 bps connection should not be used on cable lengths in excess of 15m (50 feet).
Also, a 9600 bps signal operates reliably up to a distance of approximately 30m (100 feet).
Cables of greater lengths may seem to work correctly but the connection will be less reliable.
For reliable RS-422 operation, signal ground must be connected at both ends of the cable.
Maximum cable length is 1.2 km but at 115.2 kbs it is reduced to 1 km.
Terminal Server User Guide
Introduction
Page 194