Ethernet Cable Specifications
Ethernet Cable Specifications
The Ethernet controller on the system board provides 10BASE-T and 100BASE-TX support through the RJ-45 connector on the back of your server. When you connect the server to the
network, the Ethernet controller automatically detects the data-transfer rate (10 Mbps or 100 Mbps) on the network and then sets the controller to operate at the appropriate rate.
The Ethernet controller supports the auto-detection mode only. When you install the device drivers and configure the Ethernet controller for use with the operating
system, do not select 10BASE-T mode. To ensure proper operation of the controller, always select the default parameters provided.
The following information describes the specifications for the unshielded twisted-pair (UTP) cable that can be used to connect the server to an IEEE standard 802.3 network.
To connect the server 10BASE-T or 100BASE-TX port to a 10BASE-T or 100BASE-TX port on a repeater, use a UTP cable with RJ-45 connectors at both ends. An EIA/TIA-568 Category 5 (or higher) cable must be used
for 10BASE-T and 100BASE-TX.
The 10BASE-T Ethernet and the 100BASE-TX Fast Ethernet cabling in the network must be Category 5 or higher to meet various standards, including electromagnetic compatibility.
The cables used in 10BASE-T or 100BASE-TX link segments do not require grounding. However all devices connected to this cables must be grounded.
Connect the appropriate type of UTP cable to the repeater.
- If the port on the repeater is a crossover port (also called an MDI-X port), use a UTP cable that is wired as a straight-through cable.
- If the port on the repeater is not a crossover port (also known as an MDI port), use a UTP cable that is wired as a crossover cable.
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 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.
The following table 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.
Cabling Specifications for 10BASE-T and 100BASE-TX Link Segments
| Characteristic |
Specification (see Note 1) |
| Cable type |
UTP cable with two twisted pairs
of 22, 24 or 26 AWG wire (see Note 2) |
| Nominal impedance |
100 Ohms |
| Velocity of propagation |
0.585 c (see Note 3) |
| Maximum attenuation |
° For 10BASE-T 8 to 10 dB
per 100m at 10 MHz
° For 10BASE-TX 67 dB
per 305m at 100 MHz |
NOTE:
- 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.
- The cable can contain two or four twisted pairs, but only two of the
pairs will be used by the 10BASE-T or 100BASE-TX network.
- The c represents the velocity of light traveling in a vacuum,
which is 300000 km/sec (186400 mi/sec).
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