Re: McDonnel Douglas warns against carry-on electronic devices

From:         gary@maestro.mitre.org (Gary Bisaga)
Organization: The Mitre Corporation, McLean Virginia
Date:         20 Jan 93 14:01:45 PST
References:   1 2 3 4
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In article <airliners.1993.72@ohare.Chicago.COM>, yarvin@CS.YALE.EDU (Norman Yarvin) writes:
|> drchambe@tekig5.pen.tek.com (Dennis Chamberlin) writes:
|> >The most powerful components of a CD player are presumably the motor drive
|> >and audio output.
|> Computers often have some sort of shielding, whereas the average CD player
|> probably only has as much shielding as is necessary to protect the analog
|> components from the RFI emanated by the digital components.
Except for the fact that both CD players and computers must be certified
to the (dredge memory banks for numbers and letters ...) FCC part 15J EMC
rules.  In fact, there are two parts to the rules:
- class A devices, which are built for home use
- class B devices, which are built for "commercial" use

The rules for class B devices, which often include computer equipment
(check the back of your monitor), allow a higher level of emitted
EM energy than class A devices, which would probably include CD
players, the thinking being that a device for home use is
more likely to interfere with cheap analog devices such as TV
sets and radio so must have lower EM emissions.  In any case
I'd have a hard time believing that, even subject to the same
EMC rules, a CD player would emit as much as a computer.

-- 
Gary Bisaga (gbisaga@mitre.org)