A Case For NEBS

Hi All, I was asked to forward this story on to the group. If you are on the NEBS list server, this is a duplicate. From the perspective of a telecommunications equipment manufacturer, it is good to be reminded that the extra effort and design constraints one must face to meet NEBS requirements

RE: Burn-in methods

Hi Massimo, Doug and Tania have the right idea. Basically, you want to find a combination of operational and non-operational temperature excursions that identify early life failures and manufacturing defects. This is going to be very specific to your product. A successful burn-in programs has

ITU K.41

Hi All, I am hoping that someone has had some experience the interface definitions covered in the ITU K series recommendations. My question is regarding the interface references given as Tsub1 and Tsub2 in Table 1 of K.41. This is referring to the telecommunications interface, but it is not

RE: Is 36-72VDC power supply input still valid?

Hi Paul, I am assuming that you are speaking about telecommunications switching equipment. The upper end of -72 volts supports -60V battery plant found in a few German offices with (I believe) Siemens switches. There is every indication that these systems will not spread to other offices and

RE: NEBS/telco LED alarm color

Hi Dwight, From GR499:Dec 1995: R12-2 [313] The following color conventions shall be adhered to: RED To indicate critical or major failure, error, or danger YELLOW To indicate a minor failure, caution, warning, or temporary malfunction GREEN To indicate satisfactory

RE: Testfacilities GR-1089-Core

Hi Chris, The correct response to this question is: Check with your prospective customers. Each RBOC and CLEC has a different bent on who's tests they will accept and there are always exceptions to the hard and fast operating procedures proclaimed at the annual conferences. There are many labs

RE: Zo

Hi William, This is a dynamic quantity dependent on the size of the wire, number of twists, and frequency range of interest. You can get a lot of good information from the web pages of various twisted pair cable manufacturers. The normal impedance for twisted pair sold as CAT 3 and CAT 5 (and

EN60950 Creepage/Clearance/HiPot

Hello Group, Happy 19101. Sorry this is so long. I thought it would be easier for replies if the categories and numbers where already written out. I am at the end of my tether trying to find out what creepage, clearance, and hipot apply to our products application. I originally tendered this

RE: internal modem

Hi Dan, You will need part 68 testing for US. A fairly large number of labs do this now. The requirement to file for a license has been simplified in the last couple of years. Make sure the design team knows that they must pass the key tests: The 600V AC power cross test (UL1459) and the

RE: PDF file copy method

Derek, Resistance is futile. You will be assimilated. Walk away from the Sun. Come back to the fold of the one true office suite god. ;-) Dave -Original Message- From: lfresea...@aol.com [mailto:lfresea...@aol.com] Sent: Monday, July 17, 2000 5:09 PM To: barry...@altavista.com;

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

RE: NEBS web site

Guy, You can get NEBS information from the NEBS list server by signing up on the RCIC website http:\\www.rcic.com in the virtual conference hall under NEBS. While most of the members of the EMC group are also on the NEBS group, it is good to send requests to the right list. To start, you will

RE: AS/NZS 4251.1.1.1999

Hi All, Thanks Laura for excellent directions! To help the direction impaired, the direct link is http://www.sma.gov.au/standards/emcbook/index.htm if you don't want to make the journey on foot ;-) Dave Spencer Oresis Communications -Original Message- From: Laura Leyba-Newton

Fanning the Flames

Hi All, I'm not sure where this question fits, so I'm sending it to all. Excuse the redundancy, as I'm sure many of you receive mail from all of these lists. An interesting question came up today regarding a fantray design and using a thermal shutdown to turn off power to the fans when it is

RE: Safety: Hi-Pot Suppression for TNV lines

Chris, Clear away the ground plane to give you the proper clearance. You need to be able to pass the tests without an external protector. You didn't mention Part 68 in your message. You do need that as well, plus an FCC Registration Number (although what you have to do to file for it may be

RE: Safety testing for 48 VDC powered ITE Equipment

Kurt, Tania is right on the money. There are other items covered in EN60950 that need to be addressed, such as lithium batteries, flammability hazard from abnormals, and bonding safety (what happens when you hook 115V up to the -48VDC input?) Also, do you supply the SELV supply? If not, you

RE: Chip noise halts Intel 820 motherboard

Filed under Things that make you go hmmm. Was this a major Product Verification screw up? Or a carefully crafted marketing plan to increase demand for RDRAM? Have a Great Day, Dave Spencer Oresis Communications -Original Message- From: Paul J Smith

RE: Receivers and spectrum analyzers

Hey Jim, It is my sincere wish to get god results from my test equipment. Alas, regardless of equipment cost, I usually wind up somewhat lower. The 8593EM is now on the top of my wish list. ;-) As to the price issue, it is very conceivable that a relatively small investment in a single feature

RE: Lightning Surge Equipment

Joe, If you are only going to do intrabuilding, you can get away with just about anything capable of the 1.2/50uSec wave form (see the provision in the GR for using this waveshape with series resistors). I am just now setting up a lab here and decided to go with Schaffner NSG2050, because it

RE: Re[2]: EMC, NEBS NRTL's

Hey All, Keep in mind that although Bell Atlantic is often the pickiest, they are not the only RBOC that flip-flops on the NRTL data issue on an annual basis. I believe US West has taken their place on the NRTL Wagon this year. Bell South weighs in on the issue regularly as well. I would not

RE: ESD wrist strap

Daniel, Just about every switch (class 4 and 5) I've ever seen has had a banana plug available. There is usually an opportunity to connect to the safety ground post, if you happen to have an alligator clip on your strap instead of the banana jack. Dave Spencer Oresis Communications

RE: EMC Test Conditions

Derek, I would like to add to Scott's comment. You are probably not going to experience any benefits from the large metallic structure. If anything, it will act as an antenna, increasing your radiated emissions and decreasing your immunity. Your concerns regarding installation are valid and

RE: Demo Units Sent to EU w/o CE ?

Jim, I have always used a label that states: Demonstration Equipment Only Not Tested for Compliance Regards, Dave Spencer Oresis Communications Compliance Engineer -Original Message- From: Lyons, Jim [mailto:jim.ly...@gtech.com] Sent: Thursday, March 02, 2000 2:29 PM To:

RE: T1/E1 compliance requirements

Hi Bob, Couple of things, mostly semantics, from my understanding: T1 and T3, are, by definition, outside plant interfaces. It has been suggested to me that the T stands for Transport. That being said, I haven't heard of anyone running T3, but if they did it would probably need to meet the

RE: 60950 - Insulation between mains and secondary with capacitor s

I think it can work. But I don't think you will like the size of the parts you will need to pass hi-pot. I think you will find it cheaper to create the barrier with a transformer than the size those capacitors will need to be. Good Luck! Dave Spencer Oresis Communications -Original

RE: Downloadable CENELEC Standards

Ooops Correction on the price...The one I quoted below was for the TRF. The standard runs 275 CHF or ~163.25 USD. Thanks for the heads up. Dave Spencer Oresis Communications -Original Message- From: David Spencer [mailto:dspen...@oresis.com] Sent: Monday, February 11, 2002 10:01 AM

RE: Downloadable CENELEC Standards

Hi All, For the cost conscious, don't forget about the IEC website, http://www.iec.ch/ You can download most of the EU and International standards in PDF or Word format. With the current exchange rate it is quite a bargain. The same EN60950:2000 costs 159 CHF (Swiss Franc) or ~94.50 USD at

RE: Earthing of conductive floor tiles

Hi Arno, John gave you the short answer...the MFG should have installation instructions. In all of the installation I have been party, there is a grid of copper tape laid down in the conductive adhesive. This keeps the adhesive from getting excessively resistive over large areas. Surface

RE: Pencil erasers for pre-EMI cleaning?

Hi Dave, Those were the days. Computer not working, pull out all the cards and take an eraser to the gold fingers. Put it back together and Voila! everything works. In a perfect world, my opinion coincides with those previously expressed. We should be testing with pristine equipment, as a