Testing Serial Port

Many times you might try to tinker with your serial port and get your external hardware interface with the serial port. In cases your serial port might not seem to respond. now the question arises if your hardware is at fault or your serial port?

The best way to test Serial Port:

Plug in a serial mouse and restart your computer. If the mouse works then you can make sure that you serial port is working perfectly. If otherwise you must check or replace your serial port.

Since most of us have shifted to USB keyboards its most common not to find one such mouse.In such cases you can try the following method.

Hyperterminal Serial Port Test:

Note the pin configuration of a male socket of a serial port.



1) Take a serial cable. Connect one end to the computer and have the other end free.

2) Short pins 2 and 3 of the side which are free . They are actually Tx and Rx pins. This setup is called NULL Modem configuration. Once the pins on the free end have been shorted you may proceed to the next step.

DB-9 :

DB 25:

3) Now you have essentially allowed a complete connection. the data that is transmitted through Tx is going to be as such received by Rx

4)Hyperterminal in windows can be used to send and receive datas.

Open Hyperterminal:

5) Open windows hyperterminal



8) Once a window opens after clicking ok. Type anything. here the phrase is “This is a Loopback test”

If you are able to type then your serial port is sending and receiving signals properly.
If you are not able to write then you’l have to check further (There might be a some problem with the port).



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