Jeffrey, I agree with David's view. The Altitude and Temp/Humidity requirements should be "AND-ed" requirements not "OR-ed" to reflect realistic deployment scenarios.
In reality, thermal analysis experts tell me that altitude does not really affect the thermal performance significantly so you should be able to pass at sea level or at 4000m equally easily (or not so easily!). The loss of heat carrying capability due to the decreased air density is off-set, at least somewhat, by the loss of pressure needed to move the air (recall the fan speed curve). Marko Radojicic email: ma...@caspiannetworks.com phone: 408/382-5206 fax: 408/382-5593 -----Original Message----- From: David Spencer [mailto:dspen...@oresis.com] Sent: Monday, September 25, 2000 9:42 AM To: 'Collins, Jeffrey'; 'emc-p...@ieee.org ' Subject: RE: NEBS: GR-63 Altitude Test Profile Hi Jeffrey, Our friends at Telcordia do seem to enjoy listing requirements where we would least expect them. GR63 is no exception. For altitude, the limits called out in R4-8 [74] and O4-10[76] for Table 4-4 are the general temperature/humidity limits for long and short term exposure. The application of those criteria can be found in Table 4.5 in the 182 hour profile. It is my belief that you test to at 4000m using the profile from table 4.5, unless you wanted to make a profile of your own that covered the same ground over a longer period of time, using Table 4-4 for the limits, rates of change, and duration. If the EUT cannot tolerate the resulting temperature rise from the 4000m altitude, it will be necessary to retest at 1800 to meet R4-8. The failure is documented in the NEBS data submitted to the carrier who decides if it is something he wants you to do something about before he purchases you equipment. I do not think it is necessary to test 1800m if you have passed the table 4-5 profile at 4000m. Don't forget: Objective requirements are not elective. The tests must be performed and the results documented. It is by this means that decisions are made about making the objective a mandatory requirement down the road. Good Luck! Dave Spencer Compliance Engineer Oresis Communications, Inc. 14670 NW Greenbrier Parkway, Beaverton, OR 97006 * dspen...@oresis.com * http://www.oresis.com * (503) 466-6289 * (503) 533-8233 -----Original Message----- From: Collins, Jeffrey [mailto:jcoll...@ciena.com] Sent: Monday, September 25, 2000 6:36 AM To: 'emc-p...@ieee.org ' Subject: NEBS: GR-63 Altitude Test Profile Group, GR-63 sections 4.1.3 & 5.1 do not give a definitive testing profile for Altitude testing. If you have completed this test what profile did you use? Is there a customer specification from an RBOC or CLEC that you found to be definitive. It appears that by only addressing these sections you could have to retest down the road for a customer located in a high altitude environment. Which Telco has the most stringent internal specifications for this test? Points to be considered are: * Max Altitude 4000m * Temperature at max Altitude Profile in Table 4-5 * Relative Humidity Profile in Table 4-5 * Length of time at Max Altitude 182 hrs Thanks in advance, Jeffrey Collins MTS, Principal Compliance Engineer Ciena Core Switching Division jcoll...@ciena.com www.ciena.com ------------------------------------------- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Jim Bacher: jim_bac...@mail.monarch.com Michael Garretson: pstc_ad...@garretson.org For policy questions, send mail to: Richard Nute: ri...@ieee.org ------------------------------------------- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Jim Bacher: jim_bac...@mail.monarch.com Michael Garretson: pstc_ad...@garretson.org For policy questions, send mail to: Richard Nute: ri...@ieee.org ------------------------------------------- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Jim Bacher: jim_bac...@mail.monarch.com Michael Garretson: pstc_ad...@garretson.org For policy questions, send mail to: Richard Nute: ri...@ieee.org
