RS232 Null Modem > RS232 (DB9)

Discussion in 'The Projects Forum' started by MR_ROB30, Jun 26, 2012.

  1. MR_ROB30

    Thread Starter New Member

    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.
  2. upand_at_them

    Active Member

    May 15, 2010
    You can buy USB-to-UART adapters on eBay.
  3. Sensacell

    Well-Known Member

    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.