In a message dated 7/22/2002, Muhammad writes:
> For boards with copper ports (100baseT and 100base T), is it possible to use > rj45 connectors with integrated magnetics and still get pass these tests. Hi Muhammad: Previous respondents have clarified that typically you will be subject to the intrabuilding lightning surges and the 120 VRMS power cross test. They have also noted that you can avoid the lightning tests if you use a shielded cable that is grounded on both ends (although such grounding creates its own EMC issues that this group has discussed previously). In the past, I have avoided using the RJ-45 jacks with integrated magnetics because I was skeptical about their ability to survive the lightning surges. The very thin wire used on the windings is susceptible to damage from the 100 amp differential surge, and the isolation barrier is susceptible to damage from the 1500 volt common mode surge. You can probably provide adequate differential protection to protect the winding wire during the differential surge, but the isolation barrier has to take the full 1500 volt common mode surge (providing protection to ground would not be cost effective or space-efficient). If you locate a supplier of integrated magnetics that claims they survive the intrabuilding surges, I would be interested to know. In the absence of a GR-1089 compliant, integrated-magnetics device, the two most viable options are: 1) Use an RJ-11 with integrated magnetics and then use the shielding exemption to avoid the lightning tests. 2) Use external magnetics with more robust isolation that can handle the 1500 volt common mode surge. I have used the second approach successfully on several designs where NEBS compliance was required. Joe Randolph Telecom Design Consultant Randolph Telecom, Inc. 781-721-2848 http://www.randolph-telecom.com
