RS232 null modem cable (DB25-DB25)
Use this cable between two DTE devices (for instance two computers).
It is the 25-pin form of the RS-232 to RS-232 connection: two computers, or a computer and an instrument that is wired as a DTE. Pin numbers follow the DB25 RS232 pinout; for 9-pin ports use the DB9-DB9 null modem cable, for a mixed pair the DB9-DB25 one.
 | DB25 pin D-SUB female to PC1 |
| DB25 pin D-SUB female to PC2 |
| DB25-1 | DB25-2 | ||
|---|---|---|---|
| Receive Data | 3 | 2 | Transmit Data |
| Transmit Data | 2 | 3 | Receive Data |
| Data Terminal Ready | 20 | 6+8 | Data Set Ready + Carrier Detect |
| System Ground | 7 | 7 | System Ground |
| Data Set Ready + Carrier Detect | 6+8 | 20 | Data Terminal Ready |
| Request to Send | 4 | 5 | Clear to Send |
| Clear to Send | 5 | 4 | Request to Send |
Note: DSR & CD are jumpered to fool the programs to think that they are online.
Our software allows you monitor, log, debug and test your RS232 or COM ports.
Null modem (crossed) cable DB9-DB25 pin
Null modem (crossed) cable DB9 to DB9
Modem (straight) cable (DB9-DB25)
Modem (straight) cable (DB25-DB25)
RS232 modem cable (2-wire, DB9-DB25)
Modem cable (2-wire, DB25-DB25)
RS232 connector pinouts (DB9, DB15, DB25, RJ45)