I heard from the test lab that you can use a "good system" as your
peripherals to test your EUT rather than test it with a "worst system"
to obtain worst case for CE and FCC compliance, is that right? As I
know for CE and FCC, they only require a "typical system", so you can
choose your "favorite system". Any comments?
Regards,
Roger Hsu
______________________________ Reply Separator _________________________________
Subject: RE: Peripherals
Author: Gary McInturff <[email protected]> at Internet
List-Post: [email protected]
Date: 9/2/98 10:09 AM
Dan,
Thank you very much for providing the paragraphs. I happen to be
away from my office and can't get to these documents handily. I follow
your logic on the DoC equipment modifications thread but (theirs always
a but(t)). We are now discussing interpretation and intent. I think that
the FEDS are allowing for a change in the field during test time. The
assumption is that you make a change that will be manufacturable. In
fact I always re-test to insure this is true, particularly if it is a
mechanical rather than component value change. As a manufacturing of the
actual EUT I have control over the production of the test item. I don't
have that luxury with other vendors equipment. They could change it, but
let's face it they are more likely to tell you that the only people they
have a problem with is when your equipment, and do nothing. So in this
case documenting the change doesn't really solve the problem unless you
were to modify each peripheral as well.
I guess I should point out that I don't have a huge problem. On
occasion I have some troubles with somebody else's stuff and I have no
reason to believe it to be anything other than the single sample I
happen to be looking at. Its more that I don't have the time in the
schedule, or the nature to mess around during tests. I look for rock
solid peripherals and won't use one unless I first check it out and am
satisfied that it not only meets the limits but provides some margin to
those limits.
Thanks again Dan.
Gary
-----Original Message-----
From: [email protected]
[SMTP:[email protected]]
Sent: Tuesday, September 01, 1998 12:52 PM
To: [email protected]; [email protected]
Cc: [email protected]
Subject: Re: Peripherals
All,
I believe you guys are referring to 47CFR2.1033,
Application for certification:
(8) If the equipment for which certification is being
sought
must be tested with peripheral or accessory devices
connected
or installed, a brief description of those peripherals
or
accessories. The peripheral or accessory devices shall
be
unmodified, commercially-available equipment.
See also the previous section, 47CFR2.1031:
The general provisions of this subpart [section] 2.901
et seq.
shall apply to applications for and grants of
certification.
As for products only subject to a Declaration of Conformity,
there is this requirement in 47CFR2.1075a (Retention of
records):
(1) A record of the original design drawings and
specifications
and all changes that have been made that may affect
compliance with the requirements of [section] 2.1073.
My interpretation is that unmodified, commercially-available
support equipment are only required for FCC Certification.
For Declarations of Conformity, I would take the
retention-of-records
requirements one step further. I would not modify support
equipment
unless it does not disguise emissions from the EUT, and I would
justify it in the test report per 47CFR2.1075a3 (Retention of
records):
(iv) A description of the equipment under test (EUT) and
support equipment connected to, or installed within, the
EUT;
To be fair, one argument against my intepretation is the
following
section, which explicitly requires that modifications
to the EUT (but not support equipment,) be documented:
(viii) A description of any modifications made to the
EUT
by the testing company or individual to achieve
compliance
with the regulations;
Please also note that the requirements of 47CFR2.1075a
(Retention of records) may not apply to equipment assembled
using modular components. See 47CFR2.1075b.
My 2 cents,
Dan
> From [email protected] Tue Sep 1 11:28:03
1998
> Date: Tue, 01 Sep 1998 08:36:09 -0400
> Subject: Re: Peripherals
> To: [email protected]
> Cc: [email protected]
> From: [email protected] (Scott Douglas)
> MIME-Version: 1.0
> Content-Transfer-Encoding: 8bit
> X-Resent-To: Multiple Recipients <[email protected]>
> X-Listname: emc-pstc
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>
> Gary,
>
> I have had my problems with support equipment and peripherals
also. And,
> having used a lot of big name products, mostly computers,
etc., I was
> surprised at how many of them failed when my product was
turned off and
> theirs was left running. It is quite common for test house
guys to say "
> Oh, that's the host, we'll ignore that one". I finally got to
the point
> where I put them outside the test environment, i.e. below the
floor or
> outside the shield room. I do this because I don't sell them
and figure
> that if I run self test mode and don't see the problem, then
it is either
> the other guy's stuff or my I/O. If it is my I/O, I will fix
it. If it is
> the other guy's stuff, I leave it alone. I can't / won't fix
their
> non-compliant equipment, don't have either the time or money
to do so. I
> did eventually find a quiet PC and monitor which I guard with
my life. I
> have even coerced the software guys into making their latest
stuff play
> with my older PC so I can keep using it.
>
> I can't point to the reference you are asking for. It seems to
me that if
> the support / host equipment is required to be on the table
during test,
> then the entire thing must comply. It can be difficult to
point the finger
> at one piece and say that it is the source of the problem,
especially on
> the immunity side. If you try several different pieces of
support
> equipment and the "system" continues to fail, it probably is
within the
> common unit, i.e. your product. If you find that changing the
support
> equipment can make the "system" pass, then either you have a
marginal
> product or a too-sensitive support equipment. In this case,
you have a
> decision to make, and a tough one at that. Sorry I am not more
help on
> this one.
>
> Regards,
> Scott
> [email protected]
>
>
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