How to test RS232 Serial Port

[Neo]

Note that the DB9 female-to-DB9 male serial cable available in the market is a one-to-one extension cable. This means when you plug the female side to the computer, you have exactly the same port in computer on the male side.

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If you need to test your serial port, you can do a loopback test.
Short the pins 2 and 3 with a 1 K? resister as below, open the port is Hyper Terminal with default settings (baud - 9600, parity - none, stop - 1, data - 8, handshaking - none) and type some characters on the keyboard. If you can see the same characters that you type on the screen, your serial port is working.

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