Tea Connector for Serial RS232 Cables

Step 8 Options

Null Modem connections. A null modem connection switches some of the wires around, in a 3 wire connection the receive and transmit connections are reversed. It is easy to find a switch to do this so I added one, the switch sets this up between the top row of connectors and the bottom. If you use more wires finding a switch is a pain ( and may be expensive ) In that case I would build 2 different Tea connectors, one straight through, one with a null modem connection between the upper and lower layer.