On Aug 14, 2004, at 1:54 AM, Andy Ball wrote:
> I've seen quite a bit of variation between different "null
> modem" cables.  Have you checked how yours are wired?  What
> happens if you connect the one that doesn't seem to work
> with tty01 the other way around, does it make a difference?
>
> I make mine like this...
>
>             DB  DB                        DB  DB
>              9  25                        25   9
>             ~~  ~~                        ~~  ~~
>              3   2  TXD -----\/----- TXD   2   3
>              2   3  RXD <----/\----> RXD   3   2
>
>              7   4  RTS -----\/----- RTS   4   7
>              8   5  CTS <----/\----> CTS   5   8
>
>              4  20  DTR -----\/----- DTR  20   4
>              6   6  DSR <-+--/\--+-> DSR   6   6
>              1   8  DCD <-'      `-> DCD   8   1
>
>              5   7  SG  ------------  SG   7   5
>
When we were doing the PC Weasel documentation, we decided to survey 
they various null modem cables we were able to buy from the various 
vendors and manufacturers.  We found no less than a dozen different 
pinouts that were all called "null modem".  None of them were what you 
call a null modem.  Congratulations. You've created a new species.