Hi Roger, I think when they say that they want worse case, they are referring to maximizing possible emissions from a test set up (using any compliant devices as peripherals).
If they were to request that you use the most rf-emitting peripherals that you can find, you'd be testing with a bunch of non-compliant pieces, and nobody'd be able to pass. Paul K. Chang TUV Telecom 508 460-9072 x235 -----Original Message----- From: [email protected] <[email protected]> To: [email protected] <[email protected]>; [email protected] <[email protected]>; [email protected] <[email protected]>; Gary McInturff <[email protected]> Cc: [email protected] <[email protected]> List-Post: [email protected] Date: Thursday, September 03, 1998 10:36 AM Subject: Re[2]: Peripherals > > 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 >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 > > X-Info: Help requests to [email protected] > > X-Info: [Un]Subscribe requests to >[email protected] > > X-Moderator-Address: [email protected] > > > > 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] > > > > > > --------- > > This message is coming from the emc-pstc discussion list. > > To cancel your subscription, send mail to [email protected] > > with the single line: "unsubscribe emc-pstc" (without the > > quotes). For help, send mail to [email protected], > > [email protected], or [email protected] (the list > > administrators). > > > > > >--------- >This message is coming from the emc-pstc discussion list. >To cancel your subscription, send mail to [email protected] >with the single line: "unsubscribe emc-pstc" (without the >quotes). For help, send mail to [email protected], >[email protected], or [email protected] (the list >administrators). > > > >--------- >This message is coming from the emc-pstc discussion list. >To cancel your subscription, send mail to [email protected] >with the single line: "unsubscribe emc-pstc" (without the >quotes). For help, send mail to [email protected], >[email protected], or [email protected] (the list >administrators). > > --------- This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to [email protected] with the single line: "unsubscribe emc-pstc" (without the quotes). 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