Subject:
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serial port power (was Re: when they say "fresh" batteries, they mean it!
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Newsgroups:
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lugnet.robotics
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Date:
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Tue, 17 Aug 1999 01:31:38 GMT
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Viewed:
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677 times
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In lugnet.robotics, Chris Phillips writes:
> Actually it is common practice these days to power small peripherals off of
> the supply voltage pins on RS-232 ports as long as you're not trying to pull
> tooooo much juice. [...]
Although few people remember this, back in the summer of 1994 (or maybe it was
1993) the first version of the QuickCam was announced by Connectix. (It became
a Logitech product in 1998.) It was black-and-white, with 120x160 resolution,
was ONLY available for the Macintosh (I think they did a PC version a few
months later), and connected ONLY via the serial port. They used the serial
port as the power source for the camera -- the Mac had to continuously send
fake "data" out the serial port to supply power to the QuickCam.
- Robert Munafo http://www.mrob.com
LEGO: TC+++(8480) SW++ #+ S-- LS++ Hsp M+ A@ LM++ YB64m IC13
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Message is in Reply To:
 | | Re: when they say "fresh" batteries, they mean it!
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| (...) Actually it is common practice these days to power small peripherals off of the supply voltage pins on RS-232 ports as long as you're not trying to pull tooooo much juice. And even a device with a 9-volt power supply can produce higher (...) (25 years ago, 13-Aug-99, to lugnet.robotics)
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