On 5/6/05, Rob Fell <robin.fell@email-addr-hidden> wrote:
> 1. RS232 is nominally a +/- 13v (ish) system - you don't want to ground
> anything.
> 2. It's an I/O port, and should be safe against short circuits, but I'd
> recommend using at least 1K series resistance when you're poking around
> there :)
> 3. The RS232 inputs should have pull-ups/downs to bring them to valid
> levels when disconnected.
>
> In summary - with 99% of normal sane hardware, it should work (but I'd
> recommend the precaution of a 1K resistor).
>
Hmm...so if DTR is set to +13V (0) and RTS is set to -13V (1) for
example, then I can use switches connected to CD, DSR, and CTS so that
each pin can read 0 or 1. Is that correct? Where do the resistors
go? Between DTR and the 3 switches and RTS and the 3 switches?
I'm going to refrain from making an ASCII diagram and hope I've made
myself clear.
Thanks for the suggestions, Rob.
As for the other suggestions, my box does not have a parallel port or
a gameport (Shuttle XPC). I think I can add a parallel port, but that
would cost money. I've seen a number of DIY parallel port digital
joystick interfaces, and apparently some of them even have kernel
support. A joystick port would be great, since it gives you four
analog signals (expression pedals/MIDI CCs). Alas, all I have is the
lowly serial port.
Received on Fri May 6 20:15:06 2005
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