some of the hideous cable complexity is here:
http://en.wikipedia.org/wiki/Rs232c#...TE_relative.29
the connector and pinout problem does not go away magically with pc's
its not the interfaces that go wrong - its the cables and pinouts.
there is no standardised male/female connector relationship- rs232 talks about DTE and DCE equipment which doesnt work with modern computers.
there are a whole bunch of hardware handshaking pins that may or may not need to be connected - or pulled up or pulled down - depending on the device itself.
every single device i had to use in the past used a different pinout or pinout combination.
you are lucky if your device just uses the receive and transmit pins -
but the receive and transmit pins can be wired with 2 different conventions depending on the device.