In a message dated 99-05-15 14:56:44 EDT, you write:

> hi there i seem to recall that RS232 transmissions should be done over short
>  cables. since there are only -3/+3v levels, is this true.
>
>  Since this transfer shall travel from 0.3 M - 200M i may need a potent
>  voltage level and a good shielding.
>
The RS232 specification is, in many ways, vague ... and flexible.
In a previous job, we more than once ran RS232 links over 200M+ with no
trouble, at 9600baud.
If you have good voltage levels (+/-10V min) and good error
detection/correction, you can "abuse" the spec with little risk of problems
... keep the wires away from noisy equipment ... ensure good quality joins
... etc.

Ian C.