[linux-audio-user] OT: Cell Phone RFI!

Ross Vandegrift ross at kallisti.us
Mon Dec 18 11:05:31 EST 2006

On Mon, Dec 18, 2006 at 04:45:09AM -0500, Rob wrote:
> On Monday 18 December 2006 04:26, David Baron wrote:
> > Ever read that FCC certification on the back of your machine?
> > Its interference to the outside world is below certain limits
> > and it must accept all interference from the outside. Thanks a
> > bunch.
> Even after 30 years of playing with FCC-certified toys, I've 
> never understood that wording.  Most computer equipment I've 
> used has at least SOME shielding from outside RFI, which would 
> seemingly violate the terms you're describing, which are from 
> FCC Part 15.  I've heard people claim that it was just intended 
> to provide a shield to the manufacturers against consumer 
> complaints when RFI did impair their use of the product, but I 
> would think they'd have made that a little less cryptic.

I think you've misinterpreted it.  It means that:

	a) This device does not produce RFI that causes problems with
other devices, and,
	b) this device does not break if it receives RFI from other

It's basically trying to say that the device's functionality is
neutral with respect to radio devices, even through it does produce
some amount of detectable radio frequencies.

On the other hand, you'll note that a cellphone (which is certainly
not neutral with respect to radio) carries no such FCC text.

Ross Vandegrift
ross at kallisti.us

"The good Christian should beware of mathematicians, and all those who
make empty prophecies. The danger already exists that the mathematicians
have made a covenant with the devil to darken the spirit and to confine
man in the bonds of Hell."
	--St. Augustine, De Genesi ad Litteram, Book II, xviii, 37

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