Many people do not know whether the serial cable should be crossed or directly connected. The following DB9 Curly Cable manufacturer will take you to find out.

1. Serial line interface and connection method
The DB9 Curly Cable manufacturer tells you that there are three types of male and female headers: male to female, male to male, and female to female. The above three connection lines have crossover lines and straight lines, so there are a total of 6 connection methods.
2. What is straight line and cross line?
Direct serial cable: 2 to 2, 3 to 3, 5 to 5. Cross serial cable: 2 to 3, 3 to 2, 5 to 5.
3. Why do cross and direct serial lines appear?
The DB9 Curly Cable manufacturer tells you that the standard definition of DB9 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 cable.
The DB9 Curly Cable manufacturer tells you that if you do not reverse the definition of the transceiver and the standard pins in the circuit design, you must use a crossover cable. Under normal circumstances: two female headers are crossed wires, one male and one female are straight connections. Communication conditions: RXD is connected to TXD, TXD is connected to RXD, and whether it is a cross-wire or a straight-line connection is selected according to the circuit design. Making serial cable: DB9 Curly Cable manufacturer tells you that when you only have straight cables, you can cut them off. 2 pairs of 3, 3 pairs of 2, and 5 pairs of 5 are soldered to form a crossover cable.