Hello All, We are testing Fast Transients (IEC 61000 4-4) through capacitive coupling, on USB High speed lines (480Mbps).Requirements like differential impedance (90), transient protection have been maintained. Results: 1. Our device re-enumerates during testing. But there is no data corruption. But the main processor is not reset. Re-enumeration is not accepted in our application. 2. Using a common mode choke (Recommended in INTEL guidelines for High speed USB Design) on the data lines, test was successfull. But many are saying that it is not advisable to use chokes. Using chokes may cause even enumeration problems (i.e when 2 devices are connected, one with choke another without, the devices may not enumerate) Any experience on EMI compliance with USB lines? Anybody has faced enumeration problems when multiple devices (with chokes) are connected? Please share. Regards Mani ------------------------------------------------------------------ To unsubscribe from si-list: si-list-request@xxxxxxxxxxxxx with 'unsubscribe' in the Subject field or to administer your membership from a web page, go to: //www.freelists.org/webpage/si-list For help: si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field List FAQ wiki page is located at: http://si-list.org/wiki/wiki.pl?Si-List_FAQ List technical documents are available at: http://www.si-list.org List archives are viewable at: //www.freelists.org/archives/si-list or at our remote archives: http://groups.yahoo.com/group/si-list/messages Old (prior to June 6, 2001) list archives are viewable at: http://www.qsl.net/wb6tpu