djb@wjh12.harvard.edu (David J. Birnbaum) (07/26/90)
I understand that FCC class A and B ratings identify the extent to
which electronic equipment is likely to interfere with other electronic
equipment. A class B rating, which is stricter, means that there is
less interference and that the equipment can be used in the home. A
class A rating means more interference, so that the equipment is
certified only for use in a business, where, apparently, it would be
less disruptive. I understand that owners are responsible for inter-
ference caused by their equipment and that dealers are not supposed
to sell equipment rated other than class B for home use.
Now ... what does this really mean? Can class A equipment interfere with
my neighbor's television set? At what distance? If the best system for
my needs has only class A certification, would it cripple my apartment
building if I set it up in my home office? Are there steps one can take
to increase the shielding on troublesome equipment?
Please reply by email to the following addresses. I will post a summary
(if there are any replies) in a couple of weeks.
--David
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David J. Birnbaum djb@wjh12.harvard.edu [Internet]
djb@harvunxw.bitnet [Bitnet]mvolo@uncecs.edu (Michael R. Volow) (07/28/90)
For the many of us who have built up our boxes (in my case a 386SX) from components, how does Class A or B apply? I would assume that the system as a whole would have to be tested, I would thin Or f we empirically find no TV interference, not worry about it? Michael Volow, Psychiatry, Durham VA Med Center, Durham NC 27712 919 286 0411 Ext 6933 mvolo@ecsvax.edu
eclarke@pisces.paloalto.ibm.com (Eric S. Clarke) (08/01/90)
I have a bit of experience in this area. First, class A & B certifications are not a guarantee of anything. If either a class A or a class B device causes interference with someone's TV, radio or other reception device (including telephones), you will be required to take what ever steps are necissary to eliminate the interference. For the good news, this is not really a problem. Most devices that are either class A or B will not cause any trouble. If a device does cause problems, there are several easy steps to solve most problems. First you can just move the device. Most computers don't transmit their interference more than a few feet. You can also add a more reliable ground than the original. The FCC has a good book, if you still need more help. The FCC has been hanging around a lot of computer shows recently to ensure certification compliance. As far as home-brew systems go, they have no certification. If they cause problems you will have to fix it. Eric S. Clarke UUCP: uunet!ibmsupt!eclarke 1510 Page Mill Road INTERNET: eclarke%ibmsupt@uunet.uu.net Palo Alto, CA 94304 IBM Internal: eclarke@ibmpa.paloalto.ibm.com 415-855-4458 T/L: 465-4458 IBM VNET: ECLARKE at PALOALTO