Reed Switch to RS232

Hi All,

I'm trying to ascertain how best to bring the input from a Reed
Switch to a DB9 RS232 computer port.

Here's the scenario: A friend is planning to ride the Alcan 5000
Rally in 2004 on a KTM Adventurer. I work for a software development
company who is going to write a rally program (time, distance, speed)
for him. We are mounting a tablet pc on the bike.

I can get the Reed Switch setup off the shelf for the standard
Enduro style computers easily enough. However, I'm not certain what I
need to do to bring that to an RS232 port.

Any help would be greatly, greatly appreciated. You can check out
the website for the rally at: www.alcan5000.com

Regards,
Rob

 

Reed relay?? 300 baud rate??
If so, use external power supply, -15V source thru 4.7K to input pin,
relay contacts from input pin to +15V should do the job.
I think that the negative level is a logic "one", but it has been over
30 years since i worked with teletypes.....