DB25 pinout and signals for the PC RS232 connector
This is the DB25 pinout as wired on PC COM ports, where only nine of the 25 pins carry a signal. The full RS232 port pinout (DB-25) lists all 25 signals of the standard.
 | DB25 pin D-SUB male |
| Pin | Name | Direction | Description |
|---|---|---|---|
| 1 | SHIELD | - | Shield Ground |
| 2 | TXD | → | Transmit Data |
| 3 | RXD | ← | Receive Data |
| 4 | RTS | → | Request to Send |
| 5 | CTS | ← | Clear to Send |
| 6 | DSR | ← | Data Set Ready |
| 7 | GND | System Ground | |
| 8 | CD | ← | Carrier Detect |
| 9 | n/c | - | |
| 10 | n/c | - | |
| 11 | n/c | - | |
| 12 | n/c | - | |
| 13 | n/c | - | |
| 14 | n/c | - | |
| 15 | n/c | - | |
| 16 | n/c | - | |
| 17 | n/c | - | |
| 18 | n/c | - | |
| 19 | n/c | - | |
| 20 | DTR | → | Data Terminal Ready |
| 21 | n/c | - | |
| 22 | RI | ← | Ring Indicator |
| 23 | n/c | - | |
| 24 | n/c | - | |
| 25 | n/c | - |
Note: Direction is DTE (Computer) relative DCE (Modem).
Note: Do not connect SHIELD(1) to GND(7).
Note: Do not connect SHIELD(1) to GND(7).
Our software allows you monitor, log, debug and test your RS232 or COM ports.
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