I have not seen many failure with 2.5KV surge on a power supply for FCC Part 68 tests. The duration is very small for 2.5KV. I can understand 800V Metallic surge failures. I did test many T1, DSL and external modem testing back in the FCC Part 68 /Bill von Alven days working for a Test lab in Bay Area. If the power supply is approved for product safety this should not be an issue? If the power supply was not functional after the test it cannot cause harm to the T1/PSTN. If this is a loop start device it will still meet the on hook ac/dc impedance. However, you do need to repeat all the applicable tests after surge and write what you measure/observe. I would get a second opinion from IC as the tests should be same for CS003 for PS. I would also see the wave form before applying surge to the PS. Some labs make jigs for this test and wave/amp is not correct as per TIA-968. Feel free to contact me if you have any questions. Christopher 408-470-7985
________________________________ From: Mark Gandler <[email protected]> To: [email protected]; [email protected] Sent: Friday, February 10, 2012 11:52 AM Subject: RE: [PSES] TIA-968-A failure modes, notwithstanding... Dan, "Your equipment may fail or be completely destroyed but it cannot take the network with it" this was my understanding as well (regardless of how poorly and senseless the standard written), but clearly it is not the sam understanding across the labs. Are where any guidance, f.a.q's or interpretations documents, articles published anywhere regarding this subject? "After the failure mode the applicable tests are repeated to make sure you product does not harm the network even if your product no longer operates." if the product is completely destroyed, would it be there nothing left to repeat the tests with? Mark ________________________________ From: [email protected] To: [email protected]; [email protected] Date: Fri, 10 Feb 2012 13:24:16 -0500 Subject: RE: [PSES] TIA-968-A failure modes, notwithstanding... Mark, Your equipment may fail or be completely destroyed but it cannot take the network with it. After the failure mode the applicable tests are repeated to make sure you product does not harm the network even if your product no longer operates. Dan From:Mark Gandler [mailto:[email protected]] Sent: Friday, February 10, 2012 12:48 PM To: [email protected] Subject: [PSES] TIA-968-A failure modes, notwithstanding... Group, trying to get to the bottom of the statement some of you saw many times over. Test is a power line surge, section 4.2.4 of TIA-968-A. This is a quote: "Failure Modes resulting from application of power line surge. Approved terminal equipment and approved protective circuitry shall comply with all the criteria in this standard, both prior to and after the application of the power line surge specified in 4.2.4, notwithstanding that this surge may result in partial or total destruction of the equipment under test" The use of the word "notwithstanding" is quite common throughout this standard. Been somewhat late English language acquirer, I looked it up in Merriam-Webster and easiest one for me was "in spite of". There are many different types of surge test pass/failure criteria's throughout 61000-4, GR1089 and others, from no traffic errors during the surge to it is ok if it falls apart, as long as it does not catch on fire and does not kill anyone. But these requirements are clearly defined in each standard. My question for TIA-968-A is: how can something be compliant with all the criteria in this standard "in spite of" been totally destructed? Does it mean it is ok if power adapter or power supply is dead or entire product, including voice port can be out? Test Lab did the 2.5kV test, power adapter stopped producing DC, but no arcing, burning or enclosure breach. Lab concluded the failure. I am probably missing something very obvious, so please be gentle. Thank you, Mark - ---------------------------------------------------------------- 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://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]>
