Is serial cable directly connected or crossed?

Is serial cable directly connected or crossed?


1. Serial port interface and connection method Male and female headers are divided into three types: male-to-female, male-to-male, and female-to-female. The above three types of connection lines have crossover lines and straight lines, so there are a total of 6 connection modes.

2. What is the direct connection and the crossover connection serial cable: 2 pairs 2, 3 pairs 3, 5 pairs 5. Crossover serial cable: 2 to 3, 3 to 2, 5 to 5.

3. Why are there crossover and direct serial lines? The standard DB9 definition is that pin 2 is RXD and pin 3 is TXD. When designing the circuit, some people connect pin 2 to TXD and pin 3 to RXD in order to use a direct connection. If you don’t reversely connect the transceiver and the standard pin definitions when designing the circuit, you have to use a crossover cable.

Under normal circumstances: the two female ends are cross wires, and one male and one female are straight lines. Communication conditions: RXD is connected to TXD, TXD is connected to RXD, and the choice is crossover or direct connection according to the circuit design. Make a serial cable: when there is only a straight cable at hand, you can cut it off. Welding 2 to 3, 3 to 2, and 5 to 5 is a crossover cable.