When my daughter and I watch television, one of our favorite programs is “Jimmy Neutron, Boy Genius” on the Nickelodeon cable channel. Jimmy’s common refrain when launching one of his ill-conceived inventions is, “What could possibly go wrong?” Just as unexpected things happen when Jimmy Neutron powers up one of his gizmos, sometimes IP-enabled devices don’t work correctly when connected to a network.
Cabling and Connector ProblemsUp to 60 percent of networking troubles stem from problems with the wires, plugs and sockets that make up the cabling system within a building. Even if the system was installed perfectly and met industry standards on the date it was completed, the building tenant may have modified it anytime afterwards.
A simple rule to follow is always testing all cabling and connectors for proper wiring and terminations for every job all the time. The tester I’ve been using recently is the “Resi-Tester” TP 300, manufactured by Test-Um Inc. and available at ADI. This is a great device because it not only tests 568A and B four-pair network connections, but it also provides coax and telephone connection verification. Additionally, it is a tone generator usable with many of the common probes on the market.
A problem that can appear some time after a device is initially plugged in is intermittent connectivity. This vexing situation often results from the prolonged strain of a UTP cable hanging from a jack. The weight of the cable eventually pulls the connecting pins within the plug/socket marriage loose from each other. Make sure that the cables connected to RJ-45 plugs go straight into their mating female sockets and are supported so that they don’t droop down.
Also be sure the RJ-45 plug is fully seated into the socket. Slight manufacturing variations can cause these devices to mate incorrectly or be “a little off.” The LEDs on remote devices and network switches will help indicate when a plug is properly seated. When the LED goes on, the connection is achieved.
The Right Tools for the JobFor plug installation, I use the Platinum Tools “EZ-RJ45” crimping tool and connectors, available from SES Distributors. What makes this combination the best is that competitive plug/crimper sets require the installer to exactly measure and cut the individual pairs before sticking them in the plug and applying the crimping force.
This causes two potential problems: either the technician cuts the wires a bit too short and connectivity cannot happen, or the pairs are excessively untwisted on the uncut side, increasing crosstalk between the pairs. With the EZ-RJ45 setup, the technician strips the outer jacket of the UTP cable, untwists and inserts each pair all the way through the plug, with about 1 in. sticking out from the end.
After the pairs are inserted into the plug and before crimping, the technician can pull any untwisted excess through the plug, which keeps the twisting tight on the non-cut side of the RJ-45 plug. The crimper tool cuts off the excess wires, and proper connectivity is assured every time.
A heavy-duty “110” style punch-down tool is a must for every technician. A common problem on the socket side of a connection is an individual wire that isn’t fully seated within its IDC (insulation displacement connector). Repunching the wire will usually cure the problem. Purchase a quality 110 tool such as the Siemon S814; cheap 110 tools won’t always give a solid termination, are hard to work with, and wear out quickly. I’ve used the exact same S814 on hundreds of sockets over the last 10 years.
When wiring RJ-45 sockets, I am wary of those that can be connected without using a punch-down tool. I prefer to use a “110” punch-down tool to firmly seat each wire into its IDC, and I punch each wire twice to be sure.
Just as things almost always go wrong for Jimmy Neutron, cabling and connector problems often occur. Testing all connectors and cabling, having the right tools, and knowing how to use them will eliminate these troublesome factors when connecting and troubleshooting IP-enabled security devices.
Book of the MonthTheremin: Ether Music and Espionage by Albert Glinsky
One of the best books I’ve read in the last 10 years! This is a fascinating account of the life of Leon Theremin, electronics inventor, Cold War Russian spy, and renowned Roaring ‘20s New York swinger. Learn how he invented many spying gadgets and bizarre musical instruments while wooing the ladies. Available at www.amazon.com (but there’s only a few in stock).