DE-9 (commonly called DB9) is the 9-pin D-sub connector for RS-232 serial communication used from the 1980s through today for modems, industrial equipment, GPS receivers, and embedded debug consoles.
| Pin | Name | Function | Type |
|---|---|---|---|
| 1 | DCD | Data carrier detect | BUS |
| 2 | RXD | Receive data | BUS |
| 3 | TXD | Transmit data | BUS |
| 4 | DTR | Data terminal ready | I/O |
| 5 | GND | Signal ground | GND |
| 6 | DSR | Data set ready | I/O |
| 7 | RTS | Request to send | I/O |
| 8 | CTS | Clear to send | I/O |
| 9 | RI | Ring indicator | I/O |
DE-9 (commonly called DB9) is the 9-pin D-sub connector for RS-232 serial communication used from the 1980s through today for modems, industrial equipment, GPS receivers, and embedded debug consoles.