RS232 Port (DB-25). Pinout and Signals. Full RS232 connector
 |
DB25 pin D-SUB male at the DTE (Computer) |
 |
DB25 pin D-SUB female at the DCE (Modem) |
| Pin |
Name |
Direction |
Description |
| 1 |
GND |
|
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 |
- |
- |
RESERVED |
| 10 |
- |
- |
RESERVED |
| 11 |
STF |
→ |
Select Transmit Channel |
| 12 |
S.CD |
← |
Secondary Carrier Detect |
| 13 |
S.CTS |
← |
Secondary Clear to Send |
| 14 |
S.TXD |
→ |
Secondary Transmit Data |
| 15 |
TCK |
← |
Transmission Signal Element Timing |
| 16 |
S.RXD |
← |
Secondary Receive Data |
| 17 |
RCK |
← |
Receiver Signal Element Timing |
| 18 |
LL |
→ |
Local Loop Control |
| 19 |
S.RTS |
→ |
Secondary Request to Send |
| 20 |
DTR |
→ |
Data Terminal Ready |
| 21 |
RL |
→ |
Remote Loop Control |
| 22 |
RI |
← |
Ring Indicator |
| 23 |
DSR |
→ |
Data Signal Rate Selector |
| 24 |
XCK |
→ |
Transmit Signal Element Timing |
| 25 |
TI |
← |
Test Indicator |
Note: Direction is DTE (Computer) relative DCE (Modem).
Note: Do not connect SHIELD(1) to GND(7).
Our software allows you monitor, log, debug and test any your RS232 or COM ports.
RS232 port related links
- RS232 to RS232 connect two DTE devices or computers using DB9 pin connectors.
- RS-232 - RS-232 connect two DTE devices or computers using DB25 pin connectors.
- Serial port interface serial port interface description.