Your understanding is not correct. A USB device plugged into any other device that is directly connected to the AC mains will need an oine conducted testing. Several examples are: A USB dongle that gets its power from the USB port and is plugged into a laptop where the laptop gets its power from the AC mains will require conducted emissions. The reason is simple, since the dongle gets its power >from a source that does connect to the AC mains you do not know how the dongle affects the AC mains. It is an assumption that proper filtering of the laptop power supply is sufficient to provide filtered power to the USB ports. It is also an assumption that even with filtering a USB device will not cause emissions problems for the laptop when it is plugged into the AC. While the laptop itself may only need conducted emissions originally for one sample USB device, the intentional radiator is a separate certified product and it falls under its own rules which will require conducted emissions. The FCC wants to know if the device by itself when plugged into the host device causes the host device conducted emissions problems.
Dennis Ward Evaluation Engineer American TCB Certification Resource for the Wireless Industry www.atcb.com 703-847-4700 fax 703-847-6888 direct - 703-880-4841 cell - 209-769-8316 NOTICE: This E-Mail message and any attachment may contain privileged or company proprietary information. If you received this message in error, please return to the sender. From: [email protected] [mailto:[email protected]] On Behalf Of [email protected] Sent: 04/10/2006 2:07 AM To: [email protected] Cc: [email protected] Subject: Re: Fw: FCC equipment authorization: Have RFID devices operating @ 13.56 MHz been exempted from conducted emission testing? Dear Bob, Thanks for the reply. So if a device is not drawing power from the a.c. mains it is exempted from line conducted emissions test. Similarly USB devices (such as USB mouse, USB keyboard, USB smart card reader etc.) which are drawing power from the USB port of the PC also are exempted from the line conducted emissions testing. Is my understanding correct? Sincerely K.Balasubramanian Project Leader - Hardware. [email protected] Sent by: [email protected] To [email protected] cc 04/10/2006 02:22 PM Subject Fw: FCC equipment authorization: Have RFID devices operating @ 13.56 MHz been exempted from conducted emission testing? They must be talking about the reader. It would not be subjected to line conducted tests because it is running off a 12 volt DC supply (just like any other PC board, etc.). The physical access control panel would be subjected to line conducted emission tests. Whether a device is battery backed up or not has no significance on whether it is subjected to line conducted tests. Bob Heller 3M EMC Laboratory, 76-1-01 St. Paul, MN 55107-1208 Tel: 651- 778-6336 Fax: 651-778-6252 ========================= ----- Forwarded by Robert E. Heller/US-Corporate/3M/US on 04/10/2006 03:46 AM ----- Kbalasubramanian@ scmmicro.co.in Sent by: To [email protected] [email protected] cc 04/10/2006 01:50 Subject AM FCC equipment authorisation: Have RFID devices operating @ 13.56 MHz been exempted from conducted emission testing? Dear Experts, Recently I have down loaded a test report of an intentional radiator type RFID device from the FCC website. In the report it is mentioned that line conducted emission test is not applicable due to product type. This is a physical access control reader device operating at 13.56 MHz drawing 12 volts D.C. power from a physical access control panel. The control panel is drawing power from the mains and have a battery back up too. Are devices with battery back up exempted from line conducted emission? Sincerely K.Balasubramanian Project Leader - Hardware. - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to [email protected] Instructions: http://listserv.ieee.org/request/user-guide.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] All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to [email protected] Instructions: http://listserv.ieee.org/request/user-guide.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] All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to [email protected] Instructions: http://listserv.ieee.org/request/user-guide.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] All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to [email protected] Instructions: http://listserv.ieee.org/request/user-guide.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] All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
