Structured Wiring

This page provides an introduction to help you in organizing the components of your structured wiring. You should check out the availability of the required tools and equipment before starting any installation work. Experience with running cables in an office or house and through walls with fire stopping is a plus.

Wired Ethernet (10, 100, 1000 Base T) is a good choice for data networking for multiple reasons. Security, cost and speed are the compelling features. Cat5 cabling (replaced by Cat5e) supports Fast Ethernet at a speed of 100 Mbps (100 Base T). Cat5e and Cat6 will support Gigabit Ethernet. (1000 Base T). Wireless networks are slower (20 Mbps on standards 802.11a and 802.11g ) and are subject to security threats and cost more as compared to wired Ethernet. Wireless Ethernet runs at only 6 Mbps. on standard 802.11b.

A wireless network can also be considered in addition to a wired Ethernet network. This will enable more flexibility in the distribution of data, for your office or home. For wired Ethernet, fiber optic cables may provide better performance, transmission distance, and speed but are more expensive and can be more difficult to install, especially if the connectors are attached at the job site.

Ethernet for office or home is available in three forms based on their speeds, 10 Mbps, 100 Mbps, and 1000 Mbps (gigabit) Ethernet. 10 Mbps Ethernet is an older system and is rarely used now. However 100 Mbps Ethernet (commonly known as Fast Ethernet )and Gigabit Ethernet support almost all new Ethernet components.

Cat5e has presently replaced Cat5 in general. There are legacy systems that still use Cat5 cabling . Therefore some installations may attempt to use the Cat5 installed wiring for gigabit Ethernet for short runs. This operation would have to be carefully tested to ensure correct operation. A Fluke 1800 tester would be a good choice to test for the correct setup.

Cat5 cabling systems not only support Gigabit Ethernet (1000 Mbps) for short distances, but can also accommodate 100 Mbps and 10 Mbps cabling systems. More advanced categories like Cat5e and Cat6 can also be used. Although Cat5e and Cat5 are rated for 100 Mbps, Cat5e has more headroom and higher capabilities in a number of categories. Look at the following chart to get an idea about these categories.

Specifications	Cat 5	Cat 5e	Cat 6
Frequency Range	1-100 MHz	1-100 MHz	1-250 MHz
Attenuation at 100 MHz	22 dB	22 dB	19.8 dB
NEXT at 100 MHz	32.3 dB	35.3 dB	44.3 dB
Power sum NEXT at 100 MHz	Not specified	32.3 dB	42.3 dB
Power sum ACR	Not specified	3.1 dB	15.4 dB
ELFEXT at 100 MHz	Not specified	23.8 dB	27.8 dB
Power sum ELFEXT	Not specified	20.8 dB	24.8 dB
Return Loss	16 dB	20.1 dB	20.1 dB
Propagation delay	548 ns	548 ns	548 ns
Delay skew per 100M	Not specified	45 ns	45 ns

The IEEE standard for Gigabit Ethernet is for 1000Base-T. Cat5 supports gigabit under certain conditions and some older versions of Cat5 do not support gigabit. Cat5e or Cat6 cable should be used for all new gigabit installations. Cable runs should not exceed 100 meters.

Video requires high transmission rates, and therefore it must be carefully designed for smooth running of the system. Coax cable is commonly used for local transmission of video. Fiber optic cable is also used for very high speed multiplexed video signals. For local distribution, coax video wiring can carry signals from Cable TV (CATV), local broadcast antennas, base-band video (like video from a camera) and Digital Satellite Services (DSS). In one home system, two video lines to every outlet plate allowed us to connect a TV in the basement and a DVD player in the living room to a spare TV in another room from the digital CATV converter box located in a bedroom. This saved the expense of buying multiple devices.

The widely available type video cable for structured wiring is RG6/U quad shielded coax. Generally RG6/U coax has dual shields but RG6/U quad shielded coax is also easily available. Another commonly used cable for video is the RG59. With more flexibility and slightly thinner, RG59 cables are commonly used for CATV and antenna applications. We have used RG6/U quad shielded coax because of it’s superior operating characteristics. We limit the use of RG59 to short cable runs such as from wall outlets to the TV or CD player.

Quad shielding gives higher immunity to electrical interference, therefore we do not recommend the use of RG59 due to the higher rate of signal losses in both higher and lower frequencies with digital CATV, broadband cable modems and DSS. RG6/U has less signal losses at both lower and higher frequencies especially in the longer runs of cabling.

In the past, the commonly used cable was the famous four conductor variety, which is commonly referred as Plain Old Telephone Standard (POTS). However today the minimum recommended wiring for telephone is Cat3. If you are already using CAT5 or better for you network cabling, we would recommend using the same cable for telephone as well. You can get discounts on bulk purchase of Cat5 cables and gives you the advantage of carrying four phone lines over the two lines capacity of the POTS cable.

We have been asked several times about running the telephone lines through the two unused pair of wires in Cat y (Cat3 or better). We would not recommend this as the high voltage (80 volt) ring signals of the telephone may interfere with high speed 100 Mbps or Gigabit Ethernet communications on the other wire pairs in the same cable. If all the pairs are used for phone lines, there should be no problem.

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