[plug] Serial RS-232 Pinouts

[Ian Kent]

On Fri, 07 Aug 1998, you wrote:
>Can anyone direct me to a good web site that has the details on DB9 and
>DB25 RS232 pinouts, I need to make up a DB9F to DB25F cable using a
>TP RJ-45 cable with a RJ-45 to DB9 and RJ-45 to DB25 connector on either
>end 
>

I don't know much about cabling standards, but I have picked up a little info.
over time. So, you will have to put up with not having the correct terminology
(ie DTE vs DCE) and just match the connectors.

I suggest making a short DB25--DB25 cable using one of the diagrams below and
getting a DB25 - DB25 + DB9 modem cable like the ones that often come with a
modem.

I have used this full null modem cable at home to connect PC's and to connect a
notebood to a Sun as a console device. It seems to work fine.

Full null modem cable:

  2  [>]------\ /------[<] 2  TX
               /    
  3  [<]------/ \------[>] 3  RX

  4  [>]-\           /-[<] 4  RTS
         |           |
  5  [<]-+---\   /---+-[>] 5  CTS
              \ /
  6  [<]----\  /  /----[>] 6  DSR
             \/ \/
  7  [-]-----/\-/\-----[-] 7  GND
            /  \  \ 
  8  [<]---/  / \  \---[>] 8  DCD
             /   \
 20  [>]----/     \----[<] 20 DTR


I believe that this should work for a PC also:

  2  [>]------\ /------[<] 2  TX
               /    
  3  [<]------/ \------[>] 3  RX

  4  [>]------\ /------[<] 4  RTS
               \
  5  [<]------/ \------[>] 5  CTS

  6  [<]-----\   /-----[>] 6  DSR
              \ /
  7  [-]-------\-------[-] 7  GND
              / \
 20  [>]-----/   \-----[<] 20 DTR