RS232 Null Modem > RS232 (DB9)

Thread Starter


Joined Jun 26, 2012

I have been trying to get some information about this for the past month and a half or so, but I have been unable to. I am hoping that someone here can help me.

I'm sorry if I did not post this in the correct forum. If it needs to be moved, please do so. Thanks.

I am wanting a factory to make a special type of RS232 cable for me. One end will be USB, the other will be RS232, but the RS232 portion needs to be null modem. Basically, this is the way I need it configured:

Pin2 - Pin3
Pin3 > Pin2
Pin5 > Pin5

One of the factories has sent me schematics and has asked that I change it to the way it needs to be, but due to my lack of knowledge about this and about schematics, I am unable to do so.

My questions are:
  1. Is it possible to go from USB to RS232 in a crossed way (Null Modem)?
  2. Does anyone have a schematic or diagram of how this can be done?

Any help will be very much appreciated. Thank you.


Joined Jun 19, 2012
Note that USB and RS-232 are completely different protocols.
The above mentioned converter is much more than a specially wired cable, it's a dongle with a bunch of electronics inside- needs the correct drivers installed to make it work, etc.