Hello Andy-
(Your question seems appropriate for a Friday, asked after the boss and most everyone else has left for the weekend and you're sitting at the workbench with eyes to the ceiling and palms up, waiting for the answer...) I think Joe has part of the answer, in that the impedance characteristics of telecom networks and twisted pair telecom cables are considerably different than for AC mains wiring and distribution. In addition, telecom ports (at least in the case of Ethernet based networks) may have Power over Ethernet (PoE) capability. PoE circuits from network edge devices and from midspan supplies can add substantial noise onto the already noisy Ethernet line. The IEEE 802.3 and related Ethernet standards limit the range of filtering a designer may implement in order to maximize single integrity and BW. AC mains circuits on the other hand often demand (but can tolerate) a brute force approach to noise filtering, where physical size of the filtering components is probably much less a consideration than for Ethernet interfaces and the signal is 50/60Hz, not 100MHz, plus. Just my two cents worth. Enjoy the weekend, Chet Summers Compliance Engineering Schneider Electric [email protected] From: McCallum, Andy [mailto:[email protected]] Sent: Friday, June 20, 2014 2:30 AM To: [email protected] Subject: [PSES] EN-61000-6-4 All Why are telecommunications port emissions so much higher than AC power ports? Regards Andy ______________________________________________________________________ This email has been scanned by the Symantec Email Security.cloud service. ______________________________________________________________________ - ---------------------------------------------------------------- This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. To post a message to the list, send your e-mail to <[email protected]> All emc-pstc postings are archived and searchable on the web at: http://www.ieee-pses.org/emc-pstc.html Attachments are not permitted but the IEEE PSES Online Communities site at http://product-compliance.oc.ieee.org/ can be used for graphics (in well-used formats), large files, etc. Website: http://www.ieee-pses.org/ Instructions: http://www.ieee-pses.org/list.html (including how to unsubscribe) <http://www.ieee-pses.org/list.html> List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas <[email protected]> Mike Cantwell <[email protected]> For policy questions, send mail to: Jim Bacher <[email protected]> David Heald <[email protected]> - ---------------------------------------------------------------- This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. To post a message to the list, send your e-mail to <[email protected]> All emc-pstc postings are archived and searchable on the web at: http://www.ieee-pses.org/emc-pstc.html Attachments are not permitted but the IEEE PSES Online Communities site at http://product-compliance.oc.ieee.org/ can be used for graphics (in well-used formats), large files, etc. Website: http://www.ieee-pses.org/ Instructions: http://www.ieee-pses.org/list.html (including how to unsubscribe) List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas <[email protected]> Mike Cantwell <[email protected]> For policy questions, send mail to: Jim Bacher: <[email protected]> David Heald: <[email protected]>
