Check the MBV2 cable.
http://www.devrs.com/gba/files/mbv2faqs.php

Uze/belogic

--- In gbadev@y..., "ToddnMara" <vze3357u@v...> wrote:
> Hi; I'm new to this list.
> I've got a job (probable) that needs input from a serial device
while a gba game is running. I can program the game and maybe the
comm code but are there any people here who'd like to help in this
project; I'd get money info in a few days.
> Needs a serial cable interface to a serial pic device which has been
created to comm to a pc; we want it to send little bits of data to a
game while the game is running. (standalone game)
> I'm working on the research but welcome someone who wants to work on
it from a hw/sw point of view.
> Cheers hello etc.
> Todd
>
>
> [Non-text portions of this message have been removed]