Cabletron Systems 24 User Manual

STP Cable CategoriesPage 2-62.4.1 STP Cable CategoriesThe supported STP cable types meet the following specifications:IBM Type 1 consists of two shielded twisted pairs (STP) of 22 AWG solidwire for data. Used for the longest cable runs within the walls ofbuildings.IBM Type 2 consists of six pairs of unshielded twisted pairs of 24 AWGsolid wire and a shield casing. The two pairs carried within the shieldcasing are used to carry Token Ring data. The four pairs carried outside ofthe shield casing are typically used for voice communication. Type 2 isfrequently used to wire cable runs within the walls of buildings.IBM Type 6 consists of two STP of 26 AWG stranded wire for data.Because of its high attenuation, Type 6 is used only in patch panels or toconnect devices to/from wall jacks. Attenuation for Type 6 cable is 3/2 xType 1 cable (attenuation for 66 m of Type 6 = attenuation for 100 m ofType 1).IBM Type 9 is similar to Type 1, but uses 26 AWG solid wire. Like Type 6,because of its high attenuation, Type 9 is used only in patch panels or toconnect devices to/from wall jacks. Attenuation for Type 9 cable is 3/2 xType 1 cable (66 m of Type 9 = 100 m of Type 1).2.4.2 STP Lobe LengthsThe physical length of the cable connecting a station to a TCU port on theconcentrator is referred to as the lobe length. The maximum lobe lengthattainable with the concentrator, under ideal conditions, is shown in TableTable 2-3. STP Cable Type Specifications.IBMTypeOperationalFrequency ImpedanceAttenuation per...1000 m (1000 ft)1 & 2 4 MHz ≤ 150Ω ±15% ≤ 22 dB (≤ 6.7 dB)16 MHz ≤ 150Ω ±15% ≤ 45 dB (≤ 13.7 dB)6 & 9 4 MHz ≤ 150Ω ±15% ≤ 33 dB (≤ 10.0 dB)16 MHz ≤ 150Ω ±15% ≤ 66 dB (≤ 20.0 dB)