Principles
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Glass fiber: light. Wire cabling: electrical signals. Three Primary Cable Types Twisted pair (UTP or STP) Fiber Optic
Infrared Laser Spread-spectrum radio
Cable
Characteristics
For installation in dropped ceilings; or other building spaces, cables must be plenum-rated. Cables employed in other areas may utilize the more economical polyvinyl chloride (PVC) coating.
Cables used in that space, not enclosed in a conduit, must be plenum-rated. Typically Teflon coated. Low combustibility and toxicity.
Baseband WInterlinked by repeaters.
An analog encoding scheme across a continuous range of values. Interlinked by amplifiers.
Signal travels over the single core conductor. Less susceptible to RFI, EMI and attenuation than twisted pair.
Cable manufacturers have designated Radio Government (RG) specifications for cables.
The second part indicates Baseband or broadband. The third part originally indicated the max segment length. More recently, it has been used to refer to the media.
RG 58 10base2 Thicknet Ethernet RG 8 10base5 ArcNet RG 62 10base4 (more or less)
Maximum Length of Segments: 185 meters (606.8 feet) RG-58 A/U or RG-58 C/U Coaxial Cable BNC Connectors 50 Ohm Impedance Most economical form of coax
Maximum Length of Segments: 500 meters (1640 feet) unrepeated RG-8/11Cable with external transceivers N-type Connectors, Vampire Taps, DIX connectors 50-ohm impedance Relatively expensive and difficult to work
Maximum Length of Segments: 100 meters (328 feet) Cable: Data Grade Unshielded Twisted Pair (AT&T DIW Cable, Cat. 3, or 5) RJ-45 Connectors If the cable is run through an air return use Plenum rated cable Unshielded Twisted Pair Cable Most popular form of LAN Cabling For up to 10 Mbs. Four pairs of wire per cable. For up to 100 Mbs Wiring Centers
Distribution racks, punchdown blocks and modular shelving help organize cables and permit them to be arranged vertically to conserve floor space. 10BaseFB Maximum Length of Segments: 2000 meters (5,600 feet) Cable: Typically 62.5/125 micron duplex FDDI compliant fiber optic cable ST (Straight Tip) or SC (Straight Connection) connectors
Cannot be tapped with conventional listening devices. Depending on the technology, runs can be as long as 62 miles. Takes special skills and tools to install.
How fast does the network need to be? Budget How much money can be spent on cabling? Capacity How much traffic must the network carry? How will the traffic flow?
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