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PUBLIC NOTICE
FEDERAL COMMUNICATIONS COMMISSION
     
445 12TH STREET S.W.
WASHINGTON, D.C.  20554
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                                         Internet:  http://www.fcc.gov
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DA 99-890                                                                                         Released: May 12, 1999     
                    
 
           OET CLARIFIES RULES FOR MARKETING OF CPU BOARDS

The Commission's Office of Engineering and Technology (OET) hereby clarifies certain procedures that
allow manufacturers to market Central Processing Unit (CPU) boards as separate components.  The
procedures for CPU boards sold as separate components were adopted on May 9, 1996, by Report and
Order in ET Docket 95-19, and became effective on August 19, 1996.  See 47 CFR 15.32.

CPU boards that are marketed separately are required to meet FCC standards that limit potential radio
frequency interference.  Determination of compliance with the emissions limits is necessary prior to
marketing of the CPU boards.  Section 15.32 allows two ways for manufacturers to show compliance with
the FCC's emissions limits for CPU boards.  Under Section 15.32(a)(1), the CPU board may be tested with
the cover off.  If that test does not demonstrate compliance with the emission limit but these limits are not
exceeded by more than 6 dB, it may be retested with the cover on.  Alternatively, manufacturers may use a
cover-on test, under Section 15.32(a)(2), which requires the CPU board to be marketed together with the
"specific enclosure" used for the test.

We wish to clarify how the "specific enclosure" referenced in Section 15.32(a)(2) may be identified by the
CPU manufacturer.  Manufacturers may comply with Section 15.32(a)(2) by either marketing the CPU
board together with the same model of the enclosure used for testing, or by marketing the CPU board as a
separate component and supplying the following information with the installation instructions for the CPU
board.

             The names and model numbers of sample enclosures that can be used to comply with the
   emission limits that are readily available on the market.

             A detailed description of required characteristics, such as the type of case material,
   aperture size of any openings, grounding requirements, etc., of other enclosures that may be
   used to ensure compliance with the emission limit.

             The address of a web site maintained by the CPU board manufacturer listing the above
   information and any updates.

CPU board manufacturers will continue to be responsible for compliance where assemblers or users have
followed the appropriate instructions but the complete computer does not meet the FCC emission limits for
digital devices.



     - FCC -