10BASE-T
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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 receive 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 568 standards are as follows:
25_pair_color_code_chart.png
| Pin | Pair | Wire | Color |
|---|---|---|---|
| 1 | 3 | 1 | Missing image Pair_3_wire_1_horizontal_stripe.png Pair 3 Wire 1 white/green |
| 2 | 3 | 2 | Missing image Pair_3_wire_2_horizontal_stripe.png Pair 3 Wire 2 green/white |
| 3 | 2 | 1 | Missing image Pair_2_wire_1_horizontal_stripe.png Pair 2 Wire 1 white/orange |
| 4 | 1 | 2 | Missing image Pair_1_wire_2_horizontal_stripe.png Pair 1 Wire 2 blue/white |
| 5 | 1 | 1 | Missing image Pair_1_wire_1_horizontal_stripe.png Pair 1 Wire 1 white/blue |
| 6 | 2 | 2 | Missing image Pair_2_wire_2_horizontal_stripe.png Pair 2 Wire 2 orange/white |
| 7 | 4 | 1 | Missing image Pair_4_wire_1_horizontal_stripe.png Pair 4 Wire 1 white/brown |
| 8 | 4 | 2 | Missing image Pair_4_wire_2_horizontal_stripe.png Pair 4 Wire 2 brown/white |
| Pin | Pair | Wire | Color |
|---|---|---|---|
| 1 | 2 | 1 | Missing image Pair_2_wire_1_horizontal_stripe.png Pair 2 Wire 1 white/orange |
| 2 | 2 | 2 | Missing image Pair_2_wire_2_horizontal_stripe.png Pair 2 Wire 2 orange/white |
| 3 | 3 | 1 | Missing image Pair_3_wire_1_horizontal_stripe.png Pair 3 Wire 1 white/green |
| 4 | 1 | 2 | Missing image Pair_1_wire_2_horizontal_stripe.png Pair 1 Wire 2 blue/white |
| 5 | 1 | 1 | Missing image Pair_1_wire_1_horizontal_stripe.png Pair 1 Wire 1 white/blue |
| 6 | 3 | 2 | Missing image Pair_3_wire_2_horizontal_stripe.png Pair 3 Wire 2 green/white |
| 7 | 4 | 1 | Missing image Pair_4_wire_1_horizontal_stripe.png Pair 4 Wire 1 white/brown |
| 8 | 4 | 2 | Missing image Pair_4_wire_2_horizontal_stripe.png Pair 4 Wire 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.