Comms Testlab Wiring FAQ
RJ45 plug pin guide
| Pin # | Color | Pair | Signal |
| 1 | White/Green | 3 | Tx + |
| 2 | Green | 3 | Tx - |
| 3 | White/Orange | 2 | Rec + |
| 4 | Blue | 1 | |
| 5 | White/Blue | 1 | |
| 6 | Orange | 2 | Rec - |
| 7 | White/Brown | 4 | |
| 8 | Brown | 4 |
| Pin # | Color | Pair | Signal |
| 1 | White/Orange | 2 | Tx + |
| 2 | Orange | 2 | Tx - |
| 3 | White/Green | 3 | Rec + |
| 4 | Blue | 1 | |
| 5 | White/Blue | 1 | |
| 6 | Green | 3 | Rec - |
| 7 | White/Brown | 4 | |
| 8 | Brown | 4 |
| RJ45 | Pair | Color | RJ45 |
| 1 | 2 | White/Orange | 3 |
| 2 | 2 | Orange | 6 |
| 3 | 3 | White/Green | 1 |
| 4 | |||
| 5 | |||
| 6 | 3 | Green | 2 |
| 7 | |||
| 8 |
| RJ45 | RJ45 |
| 1 | 8 |
| 2 | 7 |
| 3 | 6 |
| 4 | 5 |
| 5 | 4 |
| 6 | 3 |
| 7 | 2 |
| 8 | 1 |
| RJ45 | Color | DB25 |
| 1 | Blue | 4 |
| 2 | Orange | 20 |
| 3 | Black | 3 |
| 4 | Red | 7 |
| 5 | Green | 1 |
| 6 | Yellow | 2 |
| 7 | Brown | 8 |
| 8 | White | 5 |
| Device 1 | Device 2 | Cable Type | Full-Duplex Possible? | Notes |
| Hub | Computer | Straight-Through | No | A |
| Computer | Computer | Cross-Over | Yes | D |
| Hub | Hub | Cross-Over | No | B |
| Router | Hub | Straight-Through | No | |
| Router | Switch | Straight-Through | Yes | D |
| Hub | Switch | Cross-Over | No | C |
| Switch | Computer | Straight-Through | Yes | D |
| Router | Computer | Cross-Over | Yes | D |
Notes:
A) "Computer" refers to PCs, Workstations, etc. ie. a device that has a NIC in it.
B) Many hubs have a MDI/MDI-X button that controls one of the ports (usually the 1st one), if the button on one of the hubs is set so that the port is in MDI mode, then a straight through cable can be used to connect the hubs rather than a cross-over cable.
C) The same as 'B', if the hub has it's port set to MDI mode then it can connect to a switch port with a straight-through cable.
D) For Full-Duplex to work, both devices must be capable of Full-Duplex mode.