IBM 847651U Handbook - Page 306

When the amber LED is on, it indicates that the Ethernet network is operating at 100 Mbps. When this LED is off, it indicates that the Ethernet network is operating at 10 Mbps. For additional information, see "Diagnostic LEDs" on page 218. Do not use telephone extension cables to connect the server to a repeater. The wire pairs in those cables are not twisted, and the cables do not meet other requirements for use in a 10BASE-T or 100BASE-TX network. You can identify telephone extension cables by their flat and thin appearance. UTP cables are rounder and thicker than telephone extension cables. Table 18 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 18. Cabling specifications for 10BASE-T and 100BASE-TX link segments Characteristic Specification Cable type UTP cable with two twisted pairs of 22, 24, or 26 AWG wire Nominal impedance 100 Ohms Velocity of propagation 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). 272 Netfinity 3000 User's Handbook