A network devices primer

A network devices primer

The Core Hardware exam focuses on the hardware used to connect a PC to a network, which boils down to the network interface card (NIC) and the cabling to which it attaches. Other hardware devices are used on a network to improve its performance or to provide an interface between different types of networks, and you should at least review these for background.

Cabling the network

In order for one computer to carry on a conversation with another computer, both computers must be able to transmit and receive electrical impulses representing commands or data. The computers and peripherals of a network are interconnected with a transmission medium to enable data exchange and resource sharing. Cable media has laid the foundation on which networks grew--literally.

Tip Although near and dear to my heart, wireless networks are not included on the A+ exams.

Primarily three types of cabling are used on most networks:

l Coaxial (coax) cable: Similar to the cable used to connect your TV set to the cable television service. Two types of coaxial cable are used on networks: thick coaxial cable (commonly called 10Base5, thickwire, or thicknet) and thin coaxial cable (10Base2, thinwire, or thinnet).

l Twisted pair (no, not the upstairs neighbors) cable: Available in two types: unshielded twisted pair (UTP) and shielded twisted pair (STP). UTP, which is by far the most commonly used network cabling, is similar to the wiring used to connect your telephone.

For use in networks, unshielded twisted pair (UTP) is clearly the most commonly used. UTP is referred to in many different ways: 10BaseT or 100BaseT, Cat 3 or Cat 5, or simply as Ethernet wire. These all translate loosely to "The moon is made of green iMacs," but they all refer to copper twisted pair wiring.

Time Shaver You may encounter some terminology relating to twisted pair copper wiring on the exams. Don't worry too much about the really technical issues surrounding each term.

l Fiber-optic cable: Glass or polymer fibers carry modulated pulses of light to represent digital data signals. Although a few different types of fiber-optic cables exist, you care about only one specific kind, and it's generally referred to as fiber-optic. Fiber-optic is also known as 10BaseF or 100BaseF.