Setting up a Serial Communication using Hyperterminal

Keywords: Serial Communication, Hyperterminal, RS232

This tutorial provide to those who are interested, a quick way to set up a serial communication. For this tutorial it is assumed that the reader:

   - wants to establish a simple serial communication between two PCs;
   - does not really want to use C or C++;

This tutorial's purpose is to respund to questions like:

   - How complicate is to set up a communication?
   - What is needed?
   - What I need is just a practical approach of this problem;


RS 232 is a standart in serial communication. An 8 bit word is transmitting one after other. The first bit sent is LSB. Some other bits are attachet to the useful bits. These bits are: START BIT, STOP BIT and some parity bits. The START BIT is the first bit sent. Then the useful package of bits are following (LSB first). The last bit sent is STOP BIT. In RS 232 standard an "1" is transmitted as -3 to -25 volts and "0" as +3 to +25 volts. Some other standard for serial communication are RS 422, RS 423, RS 485.


To set up a serial communication you will need a serial cable and a null modem. To buy a serial cable or a null modem you can try Radio Shack or Jameco. If you don't exactly know what is a "null modem" don't worry. Once you have the serial cable and the null modem (see pictures above) everything should be ok.

A serial cable and a null modem can be seen below:

Getting Started

Connect the two PCs with the serial cable and the null modem. Then, you can launch the hyperterminal. The Hyperterminal can be found as seen below:

Launch hyperterminal. You suppose to see a window like below:

Give a name to this connection, for example MEM351serial1. Hit Ok. This time, Hyperterminal will ask you to set some parameters. If your cable is connected to COM1 then hit OK. If your cable is connected to COM2 then change the setting to COM2.

Then hit OK. Another window will open and hyperterminal ask you to choose the baud rate.

Choose 9600 baud. In the "Flow control" filed choose "None" and hit OK. for BOTH PCs. Then, you can start typing and you will see the characters on the second PC. To see the characters you type on your display too, you have to make two more settings. From "File" menu, choose the "Properties" submenu.

Choose "Settings" like below:

Press the "ASCII setup" button and another window will open:

Click on the "Send line ends with line feeds" to check it and on the "Echo typed characters locally".

Hit now OK and close the window. Now, you can start typing characters and send them to the other PC. If there are any problems, please do not hesitate to email me.