10BASE-T
10BASE-T is an implementation of Ethernet which allows stations to be attached via twisted pair cable. The name 10BASE-T is derived from several aspects of the physical medium. The 10 refers to the transmission speed of 10 Mbit/s. The BASE is short for Baseband. This means only one Ethernet signal is present on the send and or recieve pair. In other words there is no Multiplexing as with Broadband transmissions. The T comes from twisted pair, which is the type of cable that is used.
10BASE-T uses RJ-45 jacks wired to either the TIA-568A or TIA-568B standard. Only the second and third pairs are used (orange and green). If the wiring standard is identical on both ends the segment is a patch cable suitable for transmission between a hub/switch/patch panel and a node. If the wiring standards are opposite on either end the segment is a crossover cable suitable for connecting a node to a node or a hub/switch to another hub/switch. The EIA/TIA 586 standards are as follows:
| Pin | Pair | Wire | Color |
|---|---|---|---|
| 1 | 3 | 1 |  white/green
|
| 2 | 3 | 2 |  green/white
|
| 3 | 2 | 1 |  white/orange
|
| 4 | 1 | 2 |  blue/white
|
| 5 | 1 | 1 |  white/blue
|
| 6 | 2 | 2 |  orange/white
|
| 7 | 4 | 1 |  white/brown
|
| 8 | 4 | 2 |  brown/white
|
| Pin | Pair | Wire | Color |
|---|---|---|---|
| 1 | 2 | 1 | white/orange
|
| 2 | 2 | 2 | orange/white
|
| 3 | 3 | 1 | white/green
|
| 4 | 1 | 2 | blue/white
|
| 5 | 1 | 1 | white/blue
|
| 6 | 3 | 2 | green/white
|
| 7 | 4 | 1 | white/brown
|
| 8 | 4 | 2 | brown/white
|
10BASE-T was the first vendor-independent standard implementation of Ethernet on twisted pair wiring. However, it was in fact an evolutionary development from AT&T StarLAN which had both 1 Mbit/s and 10 Mbit/s versions. 10BASE-T is essentially StarLAN-10 with the addition of the link-beat.
In the OSI model, 10BASE-T is at the physical layer. Ethernet encompasses both addressing at the data link layer and a number of physical-layer implementations. In this model, 10BASE-T is one of the possible physical layer standards for ethernet-- some others include 10BASE2, 10BASE5, and 100BASE-TX. Network layer protocols, such as IP, do not generally need to know whether they are being hosted on 10BASE-T or not, provided they know that they are being hosted on Ethernet.
See also
fr:10BASE-T ja:10BASE-T pl:10Base-T