• Basic Types of Network

    There are several basic types of networks appropriate for connecting computers, printers, and other devices in a small area such as a home or small office building:

  • Twisted-pair Ethernets: These run on wire that looks much like telephone wire, and are appropriate for any number of nodes within a radius of 100 meters (or somewhat larger if you add devices called "routers"). This web site tells you how to set up twisted pair Ethernets.

  • Coax-cable Ethernets: These are very much like twisted-pair Ethernets, but use wire that is more like cable-TV cable (but the cables are not interchangeable). These have a longer range, about 300 meters, but are much harder to install.

  • Fiber-optic networks: Fiber supports very high data rates, and longer distances, but is more expensive and much touchier to work with. I don't recommend trying fiber without special training.

  • Wireless networks: These are increasingly popular, and can't be beat for convenience. Within a radius of about 150 feet no wires are needed. On the other hand, range and reliability vary with wall materials, humidity, etc; and security is relatively poor. There are several variations, IEEE 802.11a (rare), 802.11b (very common), and 802.11g (new, but backward compatible with 802.11b). You need a special card for each machine, and a base station or "wireless access point" For the typical home or small office, twisted pair is the best choice for reliability, speed, and security, while wireless is the best choice for convenience. Wireless will likely be cheaper than putting connections ("drops") in every room, but more expensive than just a couple drops, such as in an office and bedroom.

  • Basic Networking Requirements

    Twisted pair Ethernets carry from 10 million bits (not bytes) per second (10Mbps) to 1 billion (1000Mbps or 1Gbps). For home use 10Mbps is typically plenty, especially because the connection out to the Internet is generally far slower than that (even a "T-1" business line is only 1.5Mbps). The wiring to support 10Mbps is called "10base-t", or CAT-3. To get a higher rate, each part of the path involved must support it: the type of wire and connectors, workmanship of wiring, Ethernet card, and hub. CAT-5 parts and workmanship can support 100Mbps or "100base-t". CAT-5e or CAT-6 parts and workmanship can support 1Gbps. CAT-7 is not yet widely used, but will support 10Gbps.

    Fortunately, high-speed networks also work fine at lower speeds: If you set up a CAT-5 network and plug in a machine whose Ethernet card only supports 10MBps, that's generally ok. Most new hubs and cards can switch automatically between 10 and 100 Mbps as needed.

    Whether doing your own work or not, top-rated wire costs very little extra. The bulk of the cost or effort is in pulling wiring into place through walls. Because of this it almost never makes sense to use less that CAT5 or CAT5e wire. Other parts such as sockets cost a little more as you go up the CAT scale, perhaps a couple dollars total per connection. If you want to save money, save on connectors not wire: that way you can upgrade later without digging around in the walls again.

    A twisted-pair network must be arranged in a "star". That is, every device must have a separate wire back to a central point, where a device called a "hub" (under $50, even for a small 1Gbps one) passes data from one wire to another. You cannot just bring the wires from multiple devices together and have it work -- unless you have only two devices total, and a special "crossover" cable.

    New phone wiring (say, from the 1990s on), is usually 3-pair (that is, 6-conductor) wire rated "CAT3", with the blue/blue-white pair used for the primary phone line. The two other pairs should handle Ethernet up to 10M bits/second. You can try wiring the other 2 pairs to an Ethernet connector and see, but it's unlikely to work. This is because house phone wiring is seldom set up as a star. Instead, builders usually hop from each room to the next with one long wire (to get them to do a star, order "home runs" for all sockets). Typically you'll have to install lots of new wire instead.

  • 1. RJ-11 (Telephone ) Plug

2. Figure 1 is the wiring scheme for the plug side of an RJ-11 connector. The diagram is shown with the "hook clip" on the underside. The typical RJ-11 connector has six terminals. Usually, only the middle four pins are used. The POTS (Plain Old Telephone Service) residential telephone wiring generally contains two pairs of wires - designed for two separate telephone lines. The center pins (Red and Green) contain the first telephone line. Please note that business (digital) phone systems may be wired differently.


3. RJ-45 (DATA) Plig Wiring

4.  Figure 2 is the wiring scheme for the plug side of an RJ-45 connector in accordance with T-568B standards. The T-568B standard is the most commonly used. The wiring diagram is shown with the "hook clip" on the underside. The wall jack may be wired in a different sequence because the wires may be crossed inside the jack. The jack should have a wiring diagram or designated pin numbers/colors to match up to the color code below. When wiring a jack or an RJ-45 plug, remember to keep the “twist” as close as possible to the (jack or plug) receptacle. This will insure compliance with Ethernet wiring standards.
Specification T-568B



5. Even pin numbers are always solid color. Odd pin numbers are white/ stripe color.)
For reference purposes only, Figure 3 details the wiring scheme according to T-568A standards. Be sure adhere to EITHER the T-568B or the T-568A standard. Do not mix different wiring specifications within the same wiring installation.



6. Specification T-568

7. Crosover Cable

Some applications may require a crossover cable. The most common use of a crossover cable occurs in wiring together two Hubs. A crossover cable “crosses over” Transmit and Receive Data. Pins 1 and 3 are crossed over, and Pins 2 and 6 are crossed over. To build a CROSSOVER cable, simply wire one side according to specification T-568B, and wire the other side according to T-568A.


8. 110 Block / 66 Block Punch-down

Punch-downs are made with the pairs in order with the white-stripe wire first, then the colored wire.
Pair 1 white/blue - Blue
Pair 2 white/orange - Orange
Pair 3 white/green - Green
Pair 4 white/brown - Brown