Actually it's to reduce interference to one's own equipment, (if it emits it - it's also susceptible to it). It also has the effect of reducing interference to other near by equipment.
Michael Sundstrom Nokia Mobile Phones, PCC EMC Technician cube 4E : 390B phone: 972-374-1462 mobile: 817-917-5021 michael.sundst...@nokia.com amateur call: KB5UKT -----Original Message----- From: EXT Ken Javor [mailto:ken.ja...@emccompliance.com] Sent: Thursday, September 07, 2000 11:43 AM To: Paolo Roncone; 'eric.lif...@ni.com' Cc: 'emc-p...@ieee.org' Subject: Re: R: Conducted Emissions on Telecom Ports Although I don't work commercial EMC on a regular basis and I do not know over what frequency range the telecom port CE are controlled (I assume here 150 kHz - 30 MHz), I believe that there is a mistaken premise inherent in the comments to which I am responding. The purpose of controlling common mode CE on any port is not to protect equipment at the other end of the cable, or other co-sited cables, but rather to control radiated emissions in a frequency range in which CE are easier to measure than RE. In turn, the purpose of controlling RE is to protect broadcast radio reception. ---------- >From: Paolo Roncone <paolo.ronc...@compuprint.it> >To: "'eric.lif...@ni.com'" <eric.lif...@ni.com> >Cc: "'emc-p...@ieee.org'" <emc-p...@ieee.org> >Subject: R: Conducted Emissions on Telecom Ports >Date: Thu, Sep 7, 2000, 9:45 AM > > > Hi Eric, > > I 100% agree with you. The scope of emissions standard should be to protect > the "outside" (i.e. public) environment from interference. So only ports > that connect to public telecom networks should be covered by the standard. > The problem is (as pointed out in one of the previous notes) that the new > CISPR22 / EN55022 standard clearly includes LAN ports in the definition of > telecommunications ports (section 3.6) no matter if they connect to the > "outside world" or not. > > Regards, > > Paolo Roncone > Compuprint s.p.a. > Italy > > -----Messaggio originale----- > Da: eric.lif...@ni.com [SMTP:eric.lif...@ni.com] > Inviato: mercoledì 6 settembre 2000 17.55 > A: emc-p...@ieee.org > Oggetto: Re: Conducted Emissions on Telecom Ports > > > All, > > As a not-quite-outside-observer (strictly EN 55011 here) of this thread, it's > not fun seeing LAN ports classified as telecom; IMO that's overkill for the > folks using EN 55022. > > Up till now, I considered a port to be telecom only if it connects a client > facility to a carrier's network (DSL, ISDN, T1 and so on). > > With repeaters every 5 meters, USB and 1394 can support a bus long enough to > connect between adjacent buildings. So, I wonder if some fanatic will soon be > promoting USB/1394 ports as telecom? > > If Chris is right, and the EN 55022 version of the old telecom port conducted > emission standard was intended to protect other telecom signals in a bundle, > then I would think that this test is clearly redundant to the immunity tests > (61000-4-6 and -4-3) that offer the needed protection from the other end. > > Does this emission requirement appear to be a waste of time and money to anyone > else? > > Regards, > Eric Lifsey > Compliance Manager > National Instruments > > > > > > > Please respond to "Chris Allen" <chris_al...@eur.3com.com> > > To: "Pryor McGinnis" <c...@prodigy.net> > cc: david_ster...@ademco.com, emc-p...@ieee.org, > gary.mcintu...@worldwidepackets.com, "John Moore" > <john_mo...@eur.3com.com> (bcc: Eric Lifsey/AUS/NIC) > > Subject: Re: Conducted Emissions on Telecom Ports > > > Pryor, > > Unfortunately, I don't think the definition is in question. It specifically > states, that for the purposes of the standard, LANs are to be considered as > telecomms ports as per section 3.6. It probably would have been less ambiguous > if the standard defined Telecomms ports as "Ports which are intended to be > connected to the telecomms network OR LANs OR similar networks. > > As far as enforcement goes this will not change from the current method of > enforcing compliance, primarily via the end user requesting DoCs and the > relevent test data to back this document up. > > I believe the requirement goes back to a test that was performed under either > VDE 0805 or 0806 (it was a long time ago that I had to perform the test). It was > specifically aimed at unscreened cables over a certain length being placed in > cable ducts and their impact on adjacent telecomms cables (if anybody remebers > StarLan this was the product I was involved in). > > Chris. > > > > > > "Pryor McGinnis" <c...@prodigy.net> on 05/09/2000 20:54:51 > > Please respond to "Pryor McGinnis" <c...@prodigy.net> > > Sent by: "Pryor McGinnis" <c...@prodigy.net> > > > To: david_ster...@ademco.com, emc-p...@ieee.org, > gary.mcintu...@worldwidepackets.com > cc: (Chris Allen/GB/3Com) > Subject: Re: Conducted Emissions on Telecom Ports > > > I do not disagree with the positions posted on this subject. My question is > how does the EU interpret and enforce this requirement/definition. > > Pryor > > ----- Original Message ----- > From: <david_ster...@ademco.com> > To: <emc-p...@ieee.org>; <gary.mcintu...@worldwidepackets.com> > Sent: Tuesday, September 05, 2000 2:07 PM > Subject: RE: Conducted Emissions on Telecom Ports > > >> >> LAN ports >> Testing Conducted RF Emissions on LAN twisted-pair lines is almost >> contrary to the intent of EN 55022 as Gary pointed out. Conducted >> emissions is more appropriate for asynchronous analog lines. >> >> LAN transmissions are digital and synchronous (except maybe ATM); the >> receiver part of the interface circuitry locks onto the frequency of >> data, rejecting spurious frequencies. The signals are truely digital, >> not analog as in a modem. >> >> Arcnet, Ethernet, and Fast Ethernet TP cabling links two points > (node, >> hub, switch, bridge) which digitally reconstitute the signal, >> eliminating spurious cable frequencies. >> >> Token-Ring is peer-peer, usually through a passive hub. Each node >> (peer) reconstitutes the signal as above. >> >> Ethernet, F-E and Token-Ring ANSI/IEEE or ISO/IEC physical layer >> requirements define interfaces, cable lengths/type(s) and timing. >> >> Coax cable rules for Arcnet, 10Base2 Ethernet) permit connection to >> multiple nodes but again, the digital nature of the signals and the >> well-defined connectivity rules prevent problems. >> >> David >> >> >> ______________________________ Reply Separator >> _________________________________ >> Subject: RE: Conducted Emissions on Telecom Ports >> Author: "Gary McInturff" <SMTP:gary.mcintu...@worldwidepackets.com> at >> ADEMCONET >> Date: 9/5/2000 10:54 AM >> >> >> Define telecom port. >> A LAN port isn't neccessarily a LAN port. Ethernet ports do not >> connect directly to the Telecommunications network - a necessary condition >> before being a telecommunications port. LANS and MANS operate all of the >> time without any use of any telecommunications equipment. Generally, >> Ethernet or Fast Ethernet for short distances and Gig Ethernet for longer >> distances. IF -- the telecommunications lines are needed there is some > sort >> of "bridge" that takes the ethernet and its digitized Voice over Internet >> Protocol (Voip) and does all of the phone stuff and makes the actual >> metallic connection. That "birdge" has the only telecommunication ports on >> it. >> Gary >> >> >> -----Original Message----- >> From: Pryor McGinnis [mailto:c...@prodigy.net] >> Sent: Thursday, August 31, 2000 6:24 AM >> To: Pettit, Ghery; david_ster...@ademco.com; emc-p...@ieee.org >> Subject: Re: Conducted Emissions on Telecom Ports >> >> >> >> Confusing isn't? >> >> ----- Original Message ----- >> From: Pettit, Ghery <ghery.pet...@intel.com> >> To: <david_ster...@ademco.com>; <emc-p...@ieee.org>; <c...@prodigy.net> >> Sent: Wednesday, August 30, 2000 5:40 PM >> Subject: RE: Conducted Emissions on Telecom Ports >> >> >> > Actually, it's August 1, 2001 as posted in the OJ on January 25th of > this >> > year. You've got 1 less month to start testing to the new standard. >> > >> > Ghery Pettit >> > Intel >> > >> > >> > -----Original Message----- >> > From: david_ster...@ademco.com [mailto:david_ster...@ademco.com] >> > Sent: Wednesday, August 30, 2000 2:04 PM >> > To: emc-p...@ieee.org; c...@prodigy.net >> > Subject: RE: Conducted Emissions on Telecom Ports >> > >> > >> > >> > The date of withdrawal of EN 55022:1998 is September 1, 2001. Look >> at >> > the NIC manual's DofC --- the mfgr. may not be declaring compliance >> to >> > conducted emissions yet. >> > >> > >> > ______________________________ Reply Separator >> > _________________________________ >> > Subject: Re: Conducted Emissions on Telecom Ports >> > Author: "Pryor McGinnis" <SMTP:c...@prodigy.net> at ADEMCONET >> > Date: 8/30/2000 10:31 AM >> > >> > >> > Hello All, >> > >> > The question originated from a manufacturer of LAN boards who sells to > end >> >> > users and to manufacturer's who integrate the LAN boards into end >> products. >> > >> > I advised the LAN board manufacturer that conducted emissions would be >> > required (with boards installed in typical host) on all LAN boards sold > to >> >> > end users and manufacturers of products that integrated LAN boards > should >> > test the ports for conducted emission in their end product. The LAN > board >> >> > manufacturer questioned double testing of the LAN boards. His concern > is >> > that boards that pass CE in a typical host may not pass in another >> > manufacturer's end product (rub of the green). The LAN Board >> manufacturer >> > ask for second opinions. >> > >> > Many thanks for your answers. >> > >> > Best Regards, >> > Pryor >> > >> > > -----Original Message----- >> > > From: Pryor McGinnis [SMTP:c...@prodigy.net] >> > > Sent: Tuesday, August 29, 2000 12:35 PM >> > > To: emc-pstc >> > > Subject: Conducted Emissions on Telecom Ports >> > > >> > > Below is a message from a non emc-pstc member. >> > > >> > > If a manufacturer purchases LAN boards which have been tested for >> > > conducted emissions in a host, is the manufacturer required to retest >> the >> > > LAN Ports for conducted emissions if the manufacturer sells his > product >> > with >> > > the LAN board installed? >> > > >> > > I am very interested in your comments. >> > > >> > > >> > > Best Regards, >> > > Pryor McGinnis >> > > c...@prodigy.net <mailto:c...@prodigy.net> >> > > www.ctl-lab.com <http://www.ctl-lab.com> >> > > >> > > ------------------------------------------- > > > > > > > > > > > ------------------------------------------- > This message is from the IEEE EMC Society Product Safety > Technical Committee emc-pstc discussion list. > > To cancel your subscription, send mail to: > majord...@ieee.org > with the single line: > unsubscribe emc-pstc > > For help, send mail to the list administrators: > Jim Bacher: jim_bac...@mail.monarch.com > Michael Garretson: pstc_ad...@garretson.org > > For policy questions, send mail to: > Richard Nute: ri...@ieee.org > > > ------------------------------------------- > This message is from the IEEE EMC Society Product Safety > Technical Committee emc-pstc discussion list. > > To cancel your subscription, send mail to: > majord...@ieee.org > with the single line: > unsubscribe emc-pstc > > For help, send mail to the list administrators: > Jim Bacher: jim_bac...@mail.monarch.com > Michael Garretson: pstc_ad...@garretson.org > > For policy questions, send mail to: > Richard Nute: ri...@ieee.org > > ------------------------------------------- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Jim Bacher: jim_bac...@mail.monarch.com Michael Garretson: pstc_ad...@garretson.org For policy questions, send mail to: Richard Nute: ri...@ieee.org ------------------------------------------- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Jim Bacher: jim_bac...@mail.monarch.com Michael Garretson: pstc_ad...@garretson.org For policy questions, send mail to: Richard Nute: ri...@ieee.org
