Ethernet Cable
Types of Ethernet Cables
Ethernet cables are classified into straight-through cables and crossover cables:
Appearance and Structure
- Straight-through cables and crossover cables are standard unshielded twisted pairs that use RJ45 connectors.
- A straight-through cable and a crossover cable have the same appearance.
Figure 7-15 and Figure 7-16 show the appearance of an Ethernet cable.
Figure 7-17 shows the structure of an Ethernet cable.
Pin Assignments
Table 7-7 lists the pin assignments of a straight-through cable.
X1 Pin |
Wire Color |
X2 Pin |
|---|---|---|
1 |
White and orange |
1 |
2 |
Orange |
2 |
3 |
White and green |
3 |
4 |
Blue |
4 |
5 |
White and blue |
5 |
6 |
Green |
6 |
7 |
White and brown |
7 |
8 |
Brown |
8 |
Table 7-8 lists the pin assignments of a crossover cable.
X1 Pin |
Wire Color |
X2 Pin |
|---|---|---|
1 |
White and orange |
3 |
2 |
Orange |
6 |
3 |
White and green |
1 |
4 |
Blue |
4 |
5 |
White and blue |
5 |
6 |
Green |
2 |
7 |
White and brown |
7 |
8 |
Brown |
8 |
To achieve the best electrical transmission performance, ensure that the wires connected to pins 1 and 2 and to pins 3 and 6 are twisted pairs.
Connection
Ethernet cables connect network devices to each other to enable the devices to communicate or to allow local maintenance and remote management.
- A straight-through cable connects a terminal (such as a PC or switch) to a network device.
- A crossover cable connects two terminals (such as PCs and switches).
Supported Cabling Types for 10GBASE-T
Table 7-9 describes the supported cabling types for a 10GBASE-T Ethernet electrical port.
Item |
Category 7 STP |
Category 6A STP |
Category 6A F/UTP |
Category 6A U/UTP |
Category 6 STP |
Category 6 UTP |
|---|---|---|---|---|---|---|
Cable Description |
Category 7 shielded twisted pair (STP) |
Category 6A shielded twisted pair |
Category 6A foiled/unshielded twisted pair |
Not supported |
Not supported |
Not supported |
Type |
Class F |
Class Ea |
Class Ea |
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Maximum transmission distance |
100 m |
100 m |
100 m |
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Cabling system bandwidth |
600 MHz NOTE:
The cabling system exceeds the requirements for IEEE 10GBASE-T performance. |
500 MHz NOTE:
The cabling system exceeds the requirements for IEEE 10GBASE-T performance. |
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- In a new built equipment room, Category 6A shielded twisted pairs or Category 7 twisted pairs are recommended. These cables can avoid alien crosstalk while having no special installation requirements. In addition, they can be used with other types of cables.
- If Category 6A foiled/unshielded twisted pairs are used in an equipment room and the cabling systems can meet requirements of TSB-155, follow these rules route these cables:
- Separate these cables with other types of cables. If they must be routed in the same cable trough with other types of cables, separated them from other cables using a metal plate.
- Separate cables as much as possible at the outlet and keep the cables parallel with each other. Most alien crosstalk appears within 20 m away from the outlet. To reduce alien crosstalk, do not bundle cables in the first 5 m to 20 m.
- If cables need to be bundled, bundle cables with cable ties placed every 150 mm to 300 mm. See Table 7-10. Bundle cables loosely, as shown in Figure 7-18.
- You are advised to add no more than 12 cables in a bundle. A bundle cannot have more than 24 cables.
