Performing an Echo Test In USB to RS232 converter

Echo testing is very useful to make sure whether a to-fro converter is working. This post is intended to give an idea about performing an echo test in a USB to RS232 converter.

The materials we need are

  1. USB to RS232 converter module
  2. A to B usb cable (printer cable)
  3. One connector wire and
  4. A computer

1) USB to RS232, 2) USB A to B cable and 3) Connector wire


Now perform the following steps.

Step1: Connect the USB cable to the module



Step2: Connect the RXD and TXD pins of the RS232 conector using the connector wire (PINs 2 and 3)




Step3: Now connect to a computer and Make sure your connections are okay.



Step4: Now open any hyper terminal software. Here we use putty. If you dont have putty download it from here. Now double click the putty.exe file and it will open. Select seraial and give the Serial line(COM port)and speed (Baudrate) you want. (Here COM5 and 9600bits/sec baudrate).


Step5: After entering the details press open. Now a black screened window will open with the port number as its label.



To know the port to which the USB to RS232 got connected Go to device manager and check under Ports (COM&LPT). If its connected with the computer then we can see the port number as indicated in the following figure.



Step6: Now type anything in the putty window (i.e. in the black screen. Make sure you are typing in the window.Not outside the window). If the converter module is working the typed data will appear in the window.


If the converter is not working the data wont appear on the screen.

Here what happened is that the data you have send through the TXD pin of the converter is “echoed” back through the RXD pin of the converter. and that data is displayed in the hyper terminal screen.That is why it is known as an ECHO test.



















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