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Why should we spend money on a good contractor?

For effective and efficient use of network computers and devices, a standards-based infrastructure is needed. Having a data cabling infrastructure that is installed to and uses components that meet industry standards ensures fewer outages and performance problems in the future. As more and more people expect 100% uptime from organizations, one of the most efficient uses of monetary resources you can make is to invest in a solid data cabling infrastructure.

But before spending any money, you should acquaint yourself with some of the basics of data cabling listed at the end of this article. This will help you talk the lingo of data cabling and understand what your contractor is saying. One hint: If your contractor has never heard of TIA/EIA 568B, move on to the next contractor. This is a standard with which every datacabling contractor should be intimately familiar.

Background on data cabling

Most computer networks use some type of media, or cable, to connect the devices on the network. The large majority of these use a grade of cable called Category 5 Unshielded Twisted Pair (CAT5 UTP). Generally each device has it own CAT5 cable to connect it to the network. So 15 computers and 2 networked printers would equal 17 individual cable runs, all leading to a central hub or switch. If all of the devices are very close to the hub or switch (less than 10 feet) the cable runs will be very short. In this scenario short CAT 5 “patch cables” can be used to connect all devices, making the job of cabling your site extremely easy. In such a case it is NOT NECESSARY to hire a data cabling contractor. Unfortunately this is not often the case. At most sites devices are located all over the building and require much longer cable runs to connect to the central hub or switch. In such cases it is usually necessary to hire a contractor.

Pre-Installation

Experience - Regardless of the job, hiring someone with experience is always desirable. Try to find a contractor that specializes in data cabling. Often electrical contractors will also offer data cabling services. This is fine--if the electrical contactor has experience or training on data cabling installations. Data cabling is very different from electrical cabling, and proper installation requires specialized knowledge. One hint for finding qualified cabling contractors in your area is to ask other businesses, such as a bank or the school district, for a recommendation. Even in rural areas and small towns, those organizations will have had some experience with a datacabling contractor. In addition, certain trade organizations, such as BICSI, may have lists of certified data cable contractors or personnel in your area. Many states also have a statewide contract for these services which are a good starting point for finding qualified contractors—even if you cannot purchase services through the state.

Make a Plan - Create a cabling plan before calling a data cabling contractor. Draw a map of your site and the locations of all your network devices. Decide where your hub or switch will be placed, and where your internet connection will connect to the network. Visualize and sketch out where all the cables will run. Plan ahead! Labor is the most expensive part of data cabling. Think about possible future expansion of your technology resources. Instead of planning for just enough cables to accommodate your existing computers, you might have the contractor run extra cables to each location in the building. This option is much less expensive than having the contractor return in a year. Also familiarize yourself with any structural issues. Are the walls solid concrete? Could cables go under the floor? Is there a dropped ceiling? This plan does not have to be technically perfect, since it is just a starting point. But it will familiarize you with your cabling requirements and help the contractor better understand your wishes

Communicate - Be sure you have a clear understanding of the contractor's plan before they get to work. Ask to see the blueprint, and walk through your site confirming that all plans meet your needs.

Technical

Cable grade - Be sure that Category 5 Unshielded Twisted-Pair cable is used (CAT5 UTP). There are lower categories of data cable. They have lower data capacity. It is unlikely a contractor would use anything other than CAT5 but if you want to be sure then examine the manufacturer stamp on the outside of the cable. This stamp identifies the category (among other things). The contractor should specify the grade of cable to be installed. If this is not identified on the paperwork, ask that it be specified before the work starts.

Jacks - every cable should terminate at the wall with a jack (fig a). Sometimes to save costs (or cut corners) data cables are not terminated with jacks. The cable will still work but the length of cable coming out of the wall will limit computer placement. If the terminated cable is has only half a meter of slack then your computer is restricted to that area. With jacks you have much more freedom. As with cable grades, the hardware used to compose a data jack should meet category 5 standards.

fig. A

Patch Panel - a patch panel is similar to a wall jack. The main difference is that a wall jack is located out on the floor where the computers are. A patch panel is located in the “back” where all of the data cables meet. A patch panel serves the same purpose as a jack. It terminates the data cables and allows for greater flexibility. Below is a picture of the front of a patch panel. This gigantic patch panel at Georgia Tech obviously connects many devices

Cable Test - Testing every new cable is absolutely essential. Most contractors will test for end-to-end connectivity. This test is good--but it is not enough. It is also important to verify that the cables can carry data. The end-to-end test sends a small signal down the cable to a tester on the other end. This test verifies a clean unbroken connection. But data transmission is a complex process. Cables may pass the end-to-end test with flying colors but fail a data transmission test. The contractor should have equipment that can test data transmission. Request a report on these tests and have the contractor explain the results. If the contractor does not have such equipment, then it is good idea to connect your network devices to the new cables and test connectivity before paying the bill or releasing the contractor. With Windows the “Local Area Connection Status” window will verify a good data connection.

Labeling - Once you have more than a handful of computers or other devices on your network, you will understand the value of labeling your cabling and patch panels. Most installers will have tools that simplify this process and it should be included as part of the cost of the installation. Every data drop, patch panel, and cable should be labeled. This will simplify troubleshooting if any problems do arise.

Post-Installation

As with any service, it is best to obtain a written guarantee and have a clear understanding of what is covered by this guarantee. Many studies show that the majority of networking problems are directly attributable to sub-standard cabling installation. Ensuring that you obtain services from a reputable cabling contractor with plenty of experience, proper tools for testing, and a willingness to stand behind their work with a guarantee will prevent headaches in the future for your organization.

Web resources:

Categories of twisted pair cabling systems

Includes the standard uses of the various categories of cable

http://searchnetworking.techtarget.com/sDefinition/0,,sid7_gci211752,00.html

Blackbox Explains Cable and Infrastructure

This well-known supplier of data cabling supplies discusses topics ranging from category 3 and above wiring standards, cable management, and cable construction. 

All About Cabling

http://ftp.linksys.com/faqs/default.asp?fqid=18

A Few Important Things to Consider When Purchasing Network Cable

http://www.networkclue.com/hardware/network/wiring.aspx

Request for Quote - Building Industry Consulting Service International, Inc. (BICSI)

BICSI is a national organization that trains cabling installers, runs educational programs, and offers an industry certification program. While this RFQ is for a large project, it is still a good template for smaller projects to see what should be asked of contractors.

http://www.bicsi.org/Content/Index.aspx?File=rfq.htm