STP Cable Categories
2.4.1STP Cable Categories
The supported STP cable types meet the following specifications:
Table
IBM | Operational |
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Impedance |
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1000 m | (1000 ft) | ||||
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1 & 2 | 4 MHz | ≤ 150Ω ±15% | ≤ 22 dB | (≤ 6.7 dB) | |
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16 MHz | ≤ 150Ω ±15% | ≤ 45 dB | (≤ 13.7 dB) | ||
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6 & 9 | 4 MHz | ≤ 150Ω ±15% | ≤ 33 dB | (≤ 10.0 dB) | |
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16 MHz | ≤ 150Ω ±15% | ≤ 66 dB | (≤ 20.0 dB) | ||
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IBM Type 1 consists of two shielded twisted pairs (STP) of 22 AWG solid wire for data. Used for the longest cable runs within the walls of buildings.
IBM Type 2 consists of six pairs of unshielded twisted pairs of 24 AWG solid wire and a shield casing. The two pairs carried within the shield casing are used to carry Token Ring data. The four pairs carried outside of the shield casing are typically used for voice communication. Type 2 is frequently 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 to connect devices to/from wall jacks. Attenuation for Type 6 cable is 3/2 x Type 1 cable (attenuation for 66 m of Type 6 = attenuation for 100 m of Type 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 to connect devices to/from wall jacks. Attenuation for Type 9 cable is 3/2 x Type 1 cable (66 m of Type 9 = 100 m of Type 1).
2.4.2STP Lobe Lengths
The physical length of the cable connecting a station to a TCU port on the concentrator is referred to as the lobe length. The maximum lobe length attainable with the concentrator, under ideal conditions, is shown in Table
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