RS232 serial port line is used for serial communication between devices and is widely applicable. The serial port line has high compatibility and the most conventional application: the desktop computer connects all kinds of serial port devices, such as computers and tax control machines, digital machine tools, PDAs, Modem, set-top boxes, barcode machines, industrial instruments and other serial port devices to communicate functions!
RS232 serial port wire connection method depends on the actual connection equipment, let's first look at its pin definition. At present, the RS232 serial port line interface is DB9 pin, RS232 serial port line interface pins are divided into two rows, how to distinguish the serial port line pins?
In the case of facing the human face and the large side of the interface facing up: one row is 5 pins, from left to right, corresponding to pins 1-5 respectively; A row of 4 pins, from left to right, corresponds to pins 6-9.
Pin, Definition, symbol
1 Carrier detection DCD
2 Receive data RXD
3 Send data TXD
4 The data terminal is ready for DTR
5 signal ground SG
6 Data ready DSR
7 Request to send RTS
8 Clear the sending CTS
9 Ringing indicates RI
So where are RS232 serial port line direct connection and interchange connection method used?
Under normal circumstances, the connection and communication of equipment and computer requires the direct connection of RS232 serial port line;
The connection communication of equipment and equipment will use the crossover line of RS232 serial port line. When choosing, users should choose RS232 serial port lines with different connection methods according to the actual situation of the connection between the two devices.
