In today’s world of personal computers, the local area network (LAN) is the meeting place where lots of things happen—and malfunctions can be disastrous. Since most installations are either coaxial cable or twisted-pair wiring, many problems encountered on a LAN are related to wiring or interconnections between the computer and the hub.
To help diagnose problems, many hand-held test instruments, such as cable testers and meters, can detect faulty connections. But even the best of these instruments and your tool box may not have what you need to make the correct connection.
One way to make the job easier is to keep a small selection of coaxial cable adapters, cable assemblies, and standard telephone plug couplers and patch cords handy. These simple, but essential, tools can make the difference between quick checks and total frustration.
For example, on a diagnostic test instrument, simply hooking the cable to the LAN tester or meter can indicate a bad cable or give a cable reading that matches the system’s needs. If there is a problem between the computer and the hub, it may be as simple as replacing the cable or wiring between the CPU and the wall plate or junction box. If the problem does not disappear, then it is isolated to the wiring in the walls or in the hub or system itself.
Ironically, working where the equipment is located often can be confining, and moving it to suit your comfort will not always be easy. The first solution is to use the cable that already is on the CPU. But you still will need a substitute to verify that the cable is or is not bad.
To keep the right items handy, select an assortment of BNC connectors and adapters, and obtain two or three cable assemblies terminated with either BNC connectors or standard telephone plugs, like an RJ-45. For twisted-pair installations, six or seven RJ-45 patch cords from 3’ to 9’ long, an RJ-45 plug-to-alligator-clip patch cord, and some RJ-45 couplers to connect patch cords end-to-end will meet most of your needs.
On the coaxial side, there are many combinations. You will need terminators for BNC (50, 75, and 100 W ) and Type N (50 and 75 W ), a BNC Tee female-male-female to monitor a line, right-angle adapters for tight areas, splices to join cables together (female-female), splices for changing gender of inputs or cables (male-male BNC and Type N connectors), 50-W BNC cable assemblies about 12″ long to connect your meter and the unit under test, and some BNC breakout adapters with alligators and grabbers for discrete connections.
Most of these accessories are available in kit form. They can save you time and avoid a lot of frustration. The accessories are really helpful when you are working in a tight spot, you cannot monitor a line in use, or you simply do not have that one little part just when you need it.
Copyright 1997 Nelson Publishing Inc.
August 1997