RJ45 to DB9/DB25 adapters are commonly used to connect from a Computer to many types of serial devices such as the APC Power Rails, Cybertec 3G Modems to a Cisco Terminal Servers. The table below covers the DB9/DB25 DTE and DCE pinouts.
| RJ45 | Function | Color | DB9F(DTE) | DB9M(DCE) | DB25F(DTE) | DB25M(DCE) |
|---|---|---|---|---|---|---|
| 1 | RTS | Blue | 7 | 8 | 4 | 5 |
| 2 | DTR | Orange | 4 | 1 | 20 | 8 |
| 3 | TX | Black | 3 | 2 | 2 | 3 |
| 4 | SG | Red | 5 | 5 | 7 | 7 |
| 5 | SG | Green | 5 | 5 | 7 | 7 |
| 6 | RX | Yellow | 2 | 3 | 3 | 2 |
| 7 | CD | Brown | 1 | 4 | 8 | 20 |
| 8 | CTS | White | 8 | 7 | 5 | 4 |
