Network Cable
You can construct an Ethernet network by using one of two different types of cable: coaxial cable, which resembles TV cable, or twisted-pair cable, which looks like phone cable. Twisted-pair cable is sometimes called UTP, or 10BaseT cable, for reasons I try hard not to explain later (in the section “Twisted-pair cable”).
You may encounter other types of cable in an existing network: thick yellow cable that used to be the only type of cable used for Ethernet, fiber-optic cables that span long distances at high speeds, or thick twisted-pair bundles that carry multiple sets of twisted-pair cable between wiring closets in a large building. For all but the largest networks, the choice is between coaxial cable and twisted-pair cable.
Coaxial cableOne type of cable that you can use for Ethernet networks is coaxial cable, usually called thinnet or sometimes BNC cable because of the type of connectors used on each end of the cable. Thinnet cable operates only at 10Mbps and is rarely used for new networks. However, you’ll find plenty of existing thinnet networks still being used.
Here are some salient points about coaxial cable:
✦ You attach thinnet to the network interface card by using a goofy twiston connector called a BNC connector. You can purchase pre-assembled cables with BNC connectors already attached in lengths of 25 or 50 feet, or you can buy bulk cable on a big spool and attach the connectors yourself by using a special tool. (I suggest buying pre-assembled cables. Attaching connectors to bulk cable can be tricky.)
✦ With coaxial cables, you connect your computers point-to-point in a bus topology. At each computer, a T connector is used to connect two cables to the network interface card.
✦ A special plug called a terminator is required at each end of a series of thinnet cables. The terminator prevents data from spilling out the end of the cable and staining the carpet.
✦ The cables strung end-to-end from one terminator to the other are collectively called a segment. The maximum length of a thinnet segment is about 200 meters (actually, 185 meters). You can connect as many as 30 computers on one segment. To span a distance greater than 185 meters or to connect more than 30 computers, you must use two or more segments with a device called a repeater to connect each segment.
Although Ethernet coaxial cable resembles TV coaxial cable, the two types of cable are not interchangeable. Don’t try to cut costs by wiring your network with cheap TV cable.
Twisted-pair cable
A popular alternative to thinnet cable is twisted-pair cable, or UTP. (The U stands for unshielded, but no one says unshielded twisted pair. Just twisted pair will do.) UTP cable is even cheaper than thin coaxial cable, and best of all, many modern buildings are already wired with twisted-pair cable because this type of wiring is often used with modern phone systems.
When you use UTP cable to construct an Ethernet network, you connect the computers in a star arrangement. In the center of the star is a device called a hub. Depending on the model, Ethernet hubs enable you to connect from 4 to 24 computers using twisted-pair cable. An advantage of UTP’s star arrangement is that if one cable goes bad, only the computer attached to that cable is affected; the rest of the network continues to chug along. With coaxial cable, a bad cable affects the entire network, and not just the computer to which the bad cable is connected.
Here are a few other details that you should know about twisted-pair cabling:
✦ UTP cable consists of pairs of thin wire twisted around each other; several such pairs are gathered up inside an outer insulating jacket. Ethernet uses two pairs of wires, or four wires altogether. The number of pairs in a UTP cable varies, but it is often more than two.
✦ UTP cable comes in various grades called Categories. Don’t use anything less than Category 5 cable for your network. Although cheaper, it may not be able to support faster networks. Although higher Category cables are more expensive than lower Category cables, the real cost of installing Ethernet cabling is the labor required to actually pull the cables through the walls. As a result, I recommend that you always spend the extra money to buy Category 5 cable
✦ The maximum allowable cable length between the hub and the computer is 100 meters (about 328 feet).
You can construct an Ethernet network by using one of two different types of cable: coaxial cable, which resembles TV cable, or twisted-pair cable, which looks like phone cable. Twisted-pair cable is sometimes called UTP, or 10BaseT cable, for reasons I try hard not to explain later (in the section “Twisted-pair cable”).
You may encounter other types of cable in an existing network: thick yellow cable that used to be the only type of cable used for Ethernet, fiber-optic cables that span long distances at high speeds, or thick twisted-pair bundles that carry multiple sets of twisted-pair cable between wiring closets in a large building. For all but the largest networks, the choice is between coaxial cable and twisted-pair cable.
Coaxial cableOne type of cable that you can use for Ethernet networks is coaxial cable, usually called thinnet or sometimes BNC cable because of the type of connectors used on each end of the cable. Thinnet cable operates only at 10Mbps and is rarely used for new networks. However, you’ll find plenty of existing thinnet networks still being used.
Here are some salient points about coaxial cable:
✦ You attach thinnet to the network interface card by using a goofy twiston connector called a BNC connector. You can purchase pre-assembled cables with BNC connectors already attached in lengths of 25 or 50 feet, or you can buy bulk cable on a big spool and attach the connectors yourself by using a special tool. (I suggest buying pre-assembled cables. Attaching connectors to bulk cable can be tricky.)
✦ With coaxial cables, you connect your computers point-to-point in a bus topology. At each computer, a T connector is used to connect two cables to the network interface card.
✦ A special plug called a terminator is required at each end of a series of thinnet cables. The terminator prevents data from spilling out the end of the cable and staining the carpet.
✦ The cables strung end-to-end from one terminator to the other are collectively called a segment. The maximum length of a thinnet segment is about 200 meters (actually, 185 meters). You can connect as many as 30 computers on one segment. To span a distance greater than 185 meters or to connect more than 30 computers, you must use two or more segments with a device called a repeater to connect each segment.
Although Ethernet coaxial cable resembles TV coaxial cable, the two types of cable are not interchangeable. Don’t try to cut costs by wiring your network with cheap TV cable.
Twisted-pair cable
A popular alternative to thinnet cable is twisted-pair cable, or UTP. (The U stands for unshielded, but no one says unshielded twisted pair. Just twisted pair will do.) UTP cable is even cheaper than thin coaxial cable, and best of all, many modern buildings are already wired with twisted-pair cable because this type of wiring is often used with modern phone systems.
When you use UTP cable to construct an Ethernet network, you connect the computers in a star arrangement. In the center of the star is a device called a hub. Depending on the model, Ethernet hubs enable you to connect from 4 to 24 computers using twisted-pair cable. An advantage of UTP’s star arrangement is that if one cable goes bad, only the computer attached to that cable is affected; the rest of the network continues to chug along. With coaxial cable, a bad cable affects the entire network, and not just the computer to which the bad cable is connected.
Here are a few other details that you should know about twisted-pair cabling:
✦ UTP cable consists of pairs of thin wire twisted around each other; several such pairs are gathered up inside an outer insulating jacket. Ethernet uses two pairs of wires, or four wires altogether. The number of pairs in a UTP cable varies, but it is often more than two.
✦ The maximum allowable cable length between the hub and the computer is 100 meters (about 328 feet).
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