Use these handy adapters to join serial devices together. This null modem adapter "cross over" the transmit (TX), receive (RX), and control lines to allow the RS-232 ports of two serial devices to communicate with each other. You will need this if you have any DTE or DCE incompatibilities. The compact size of these null modem adapters makes them ideal for tight spaces. These are available as Male-Female adapters with the following pin configuration:
| Signal |
DB9 male |
DB9 female |
Signal |
| Receive |
2 |
3 |
Transmit |
| transmit |
3 |
2 |
Receive |
| Dtr (Data Terminal Ready) |
4 |
6, 1 |
DSR (Data Set Ready), Carrier Detect |
| Ground |
5 |
5 |
Ground |
| DSR (Data Set Ready), Carrier Detect |
6, 1 |
4 |
DTR (Data Terminal Ready) |
| RTS (Request to Send) |
7 |
8 |
CTS (Clear to Send) |
| CTS (Clear to Send) |
8 |
7 |
RTS (Request to Send) |
