DB9 male Female header pin definition and connection

1. Simple introduction of physical and pin

In the development of the time will often use the serial interface, the general 9-pin serial interface is mostly. For example, as seen in:

The male female head is used in the packaging of the connecting wire. However, a 90-degree angled pin package is used for the Development Board. For example, with:

Each pin is defined as:

2. Connection of male female head to MAX232

When the male head is connected with the MAX232, we will find that according to the definition of the 9 pins, it seems that there is no difference between the male and the female, except for the appearance, as each pin definition is the same. It's not right to think like this! Careful look at the first picture will find that the male and female connections, the male head of the 2 feet connected to the female 2 feet, male 3 feet connected to the female head 3 feet. Assuming that the PIN definition will become the receiving end of the connection, the sending end of the connection. so, for the male to be able to use the PIN definition, the parent can be understood as the pin definition she is going to receive. For example, the female 2 foot is understood as she wants to connect to the receiving data side of the male header.

The following is an internal structure diagram of MAX232:

Assuming the male head, the connection method is: MAX232 (14,7) connecting the male (3),MAX232 (13,8) connecting the male (2).

assuming the female head, the connection method is: MAX232 (14,7) connection female (2), MAX232 (13,,8) connects the male (3).

The connecting line we use is usually a connecting line with a female at both ends, a male connector at both ends, and a line at one end of the male head. Test with a multimeter will find that both ends are male or female line, the inside of the line 2,3 pin is reversed, that is, one end of the 2 feet connected to the end of the 3 feet, 3 feet connected to the end of the 2 feet. And one end of the male end is a female line, one end of the 2-foot connection also has a side of the 2 feet, 3 feet connected to one end of the 3 feet.

3. The package size of the serial port

The male is the same as the female, but the pin number is not the same!

Male female head

DB9 male Female header pin definition and connection