CABLES

                        CABLES

Coaxial Cable    

• High resistance to noise; expensive

• Impedance: resistance that contributes to controlling signal (expressed in ohms) 
• Thickwire Ethernet (Thicknet): original Ethernet medium 
  –10BASE-5 Ethernet
• Thin Ethernet (Thinnet): more flexible and easier to handle and install than Thicknet   –10BASE-2 Ethernet
Twisted-Pair Cable
• Color-coded pairs of insulated copper wires twisted together
• Twist ratio: twists per meter or foot 
    – Higher twist ratio reduces crosstalk and increases attenuation 
• TIA/EIA 568 standard divides twisted-pair wiring into several categories
    – Level 1 or CAT 3, 4, 5, 5e, 6, 6e, 7 
• Most common form of cabling found on LANs today

UTP (Unshielded Twisted-Pair)

• Less expensive, less resistant to noise than STP

• Categories:

–CAT 3 (Category 3): up to 10 Mbps of data

–CAT 4 (Category 4): 16 Mbps throughput

–CAT 5 (Category 5): up to 1000 Mbps throughput

–CAT 5e (Enhanced Category 5): higher twist ratio

–CAT 6 (Category 6): six times the throughput of
CAT 5

–CAT 6e (Enhanced Category 6): reduced attenuation and crosstalk

–CAT 7 (Category 7): signal rates up to 1 GHz


             Fiber-Optic Cable

• Contains glass or plastic fibers at core surrounded by layer of glass or plastic cladding

– Reflects light back to core

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