On Thu, 31 Jul 1997 00:39:13 -0400, Roger Merchberger <zmerch(a)northernway.net>
wrote:
>Use a diode to change the -12V to 0V, and resistors
to change the +12V to
+5V .. it helps to have a cable to test first for that one,
tho. On the
Tandy PDDs, the resistor value was 22K Ohms IIRC and any cheap .6V drop
diode would do (read: 1N914 -- everybody's buddy)<<
It's funny that you said this. I just looked at an RS-232 level shifter
circuit on the MIT MiniBoard robotics controller that used a transistor, two
LEDs and a handful of resistors to accomplish that, but it needs 5v to
operate. Really what I need is a parasitic converter that's powered off of the
serial port itself. I've seen this done with a MAX232 or a Dallas 12?? chip.
Hmmmm, time to circuit-hunt.
-------------------------------------------------
Rich Cini/WUGNET
e-mail: rcini(a)msn.com
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