Unshielded and shielded Tp Unshielded Twisted Pair (UTP) Ord inary telephone wire Easiest to install Suffers from external electromagnetic interference UTP categories EIA-568-A: Commercial Building Telecommunications Cabling Standard Category 3 The transmiss ion characteristics are specified up to 16MHz Eg, the attenuation at 16MHz is about 13db per 100m Voice grade found in most ofices Twist length: 7.5 cm to 10 cm Category 5 The transmiss ion characteristics are specified up to 100MHz Eg, the attenuation at 16MHz is about 8db per 100m, the attenuation at 100MHz is about 22db per 100m Commonly pre-installed in new office buildings Twist length: 0.6 cm to 0.85 cm Remark: Category 3 Category 5 cables are widely used in LAN Shielded Twisted Pair(STP) Metal braid or sheathing that reduces interference 二 More expensive Harder to handle(thick, heavy) 88 Unshielded and Shielded TP • Unshielded Twisted Pair (UTP) — Ordinary telephone wire — Cheapest — Easiest to install — Suffers from external electromagnetic interference • UTP categories — EIA-568-A: Commercial Building Telecommunications Cabling Standard — Category 3 • The transmission characteristics are specified up to 16MHz – E.g., the attenuation at 16MHz is about 13db per 100m • Voice grade found in most offices • Twist length: 7.5 cm to 10 cm — Category 5 • The transmission characteristics are specified up to 100MHz – E.g., the attenuation at 16MHz is about 8db per 100m, the attenuation at 100MHz is about 22db per 100m • Commonly pre-installed in new office buildings • Twist length: 0.6 cm to 0.85 cm — Remark: Category 3 & Category 5 cables are widely used in LAN. • Shielded Twisted Pair (STP) — Metal braid or sheathing that reduces interference — More expensive — Harder to handle (thick, heavy)