unable to establish serial connection between 2 serial ports of same laptop

[mniedernhuber]

I know an USB to RS232 converter where the Rx Tx are NOT ant pin 2 and 3, Ground Pin 5.

Check the Pin configuration of your converter. I know an converter where Rx and Tx are on

Pin 1 and 2. A NULL modem cable only works if your converter has Rx and Tx on pin 2 and 3.

[crossrulz]

Use this VI for testing your serial connection.  It avoids the race conditions of setting up the ports and makes sure the read is done after the write.

[Ranjeet_Singh]

Hi CHINTAN_11NOV,

                                    Tell me first you are using same PC and 2 different ports or 2 different PCs. I didnt read properly your question

[CHINTAN_11NOV]

i want to do it for two different pc, i have also tried for two different com port of same pc but failed in both case. finally i want to make etwork of three or for pc using single serial line

[Ranjeet_Singh]

Please stick with 2 PC and run what i gave you with latest Tx. Let me know the Error out values

[crossrulz]

This is sounding like a hardware problem.  For that reason, stick with a single computer with 2 serial ports.  It'll be easier to debug that way.  It also might be time to pull out the oscilloscope to make sure the signals are going where they are supposed to.  Also, as already mentioned, make sure the USB adapter puts the RX and TX where you expect them.