The RJ-45 connector is commonly used for network cabling and for telephony applications. It's also used for serial connections in special cases. Here's a look at it:
Pinout for Ethernet
Although used for a variety of purposes, the RJ-45 connector is probably most commonly used for 10Base-T and 100Base-TX Ethernet connections.
|
Pin # |
Ethernet
10BASE-T |
EIA/TIA 568A |
EIA/TIA 568B or AT&T 258A |
|
1 |
Transmit + |
White with green strip |
White with orange stripe |
|
2 |
Transmit - |
Green with white stripe or solid green |
Orange with white stripe or solid orange |
|
3 |
Receive + |
White with orange stripe |
White with green stripe |
|
4 |
N/A |
Blue with white stripe or solid blue |
Blue with white stripe or solid blue |
|
5 |
N/A |
White with blue stripe |
White with blue stripe |
|
6 |
Receive - |
Orange with white stripe or solid orange |
Green with white stripe or solid |
|
7 |
N/A |
White with brown strip or solid brown |
White with brown strip or solid brown |
|
8 |
N/A |
Brown with white stripe or solid brown. |
Brown with white stripe or solid brown. |
Because only two pairs of wires in the eight-pin RJ-45 connector are used to carry Ethernet signals, and both 10BASE-T and 100BASE-TX use the same pins, a crossover cable made for one will also work with the other.
Also, please note that it is very important that a single pair be used for pins 3 and 6. If one conductor from one pair is used for pin 3 and a conductor from another pair is used for pin 6, performance will degrade. See the following figure.
To learn more about Ethernet, check out Charles Spurgeon's Ethernet Reference.
RJ-45 Pinout for RocketPort
The following chart shows the pinout for RJ-45 connectors used on certain RocketPort serial interface cards (manufactured by Comtrol).
| Pin | Name/Description |
|---|---|
| 1 | Request To Send |
| 2 | Data Terminal Ready |
| 3 | Ground |
| 4 | Transmit Data |
| 5 | Receive Data |
| 6 | Data Carrier Detect |
| 7 | Data Set Ready |
| 8 | Clear To Send |
Pinouts for ISDN
Here's an ISDN BRI U port pinout for a Cisco 750 series router:
| Pin | Function |
|---|---|
| 1 | Not used |
| 2 | Not used |
| 3 | Not used |
| 4 | U interface network connection (tip) |
| 5 | U interface network connection (ring) |
| 6 | Not used |
| 7 | Power (pass-through to S connector) |
| 8 | Ground (pass-through to S connector) |
The following chart shows the pinout for RJ-45 connectors used on certain ISDN S/T interfaces. For more info, see ANSI T1.605.
| Pin | Color | Name/Description |
|---|---|---|
| 1 | White/Orange | N/A |
| 2 | Orange | N/A |
| 3 | White/Green | Receive+ |
| 4 | Blue | Transmit + |
| 5 | White/Blue | Transmit - |
| 6 | Green | Receive - |
| 7 | White/Brown | -48VDC (optional) |
| 8 | Brown | -48VDC Return (optional) |