IBM 847681U Hardware Maintenance Manual - Page 62

Table 1 on page 54 describes the specifications for UTP cables used in 10BASE-T and 100BASE-TX link segments. Cables for these link segments must be certified as EIA/TIA-568 Category 5. Table 1. Cabling Specifications for 10BASE-T and 100BASE-TX Link Segments Characteristic Cable type Nominal impedance Velocity of propagation Specification UTP cable with two twisted pairs of 22, 24, or 26 AWG wire 100 Ohms 0.585 c Maximum attenuation For 10BASE-T: 8 to 10 dB per 100 m at 10 MHz For 100BASE-TX: 67 dB per 305 m at 100 MHz Notes: 1. Cables that have been certified as EIA/TIA-568 Category 5 meet all 10BASE-T and 100BASE-TX specifications. An EIA/TIA-568 Category 5 cable must be used for 10BASE-T and 100BASE-TX. 2. The cable can contain two to four twisted pairs, but only two of the pairs will be used by the 10BASE-T or 100BASE-TX network. 3. The c represents the velocity of light traveling in a vacuum, which is 300 000 km/sec (186 400 mi/sec). Note AWG = American Wire Gauge EIA = Electronics Industries Association STP = shielded twisted pair TIA = Telecommunications Industries Association The following figure illustrates the RJ-45 connector. 10BASE-T or 100 BASE-TX UTP Cable 1 23 Pins 6 RJ-45 Modular Plug Connector The following figure illustrates the wiring in straight-through cables. RJ-45 Modular Connector 10BASE-T / 100 BASE-TX RJ-45 Modular Connector Twisted Signal Pair Name Pin 1 TD+ 1 Signal Pin Name 1 TD+ 1 TD 2 2 TD 2 RD+ 3 3 RD+ 2 RD 6 6 RD 3, 4 (Not used) 4, 5, 7, 8 Relative to the device connected to the adapter 4, 5, 7, 8 (Not used) 54 Netfinity Server HMM