Conference netcad::hub_mgnt

    My hard-copy of the DECswitch 900EF installation guide dated
    May 1995 shows the altitude limit as being 4900m (16,000 ft).
    I'm pulling a soft-copy of the D01 rev May 1996 to see what it
    says.
    
    Bob

    
    The latest manual is on the WEB. It is dated May 1996. This version
    now lists the non-operating and operating specifications. 
    
    See the manual on the WEB for the numbers.
    
    Mary Peraro
    Hardware Doc Project Leader
    

    Yup, I've got the May 1996 manual in my hands, and as Mary
    alluded to, the rev D01 lists both the operating and non-operating
    altitude.
    
    
    Altitude
    
    - Operating         Sea level to 2400 m (8,000 ft)
    - Non-operating     Sea level to 4900 m (16,000 ft)
                        For sites above 2400 m (8,000 ft) decrease the
                        operating temperature specification by 1.8 deg C
                        for each 1000 m or 3.2 deg F for each 3200 ft.
    
    My recollection of the DEC standard that altitude specs are associated 
    with is that there has always been an operating and non operating limit.
    I suspect that the singular previous altitude limit documented of
    4900 m  was not a clear and accurate way to document the altitude
    limits. Presumably all manuals, as they are updated for other reasons, 
    will now adhere to the proper procedure of documenting operating and 
    non-operating limits. 
    The higher altitude limits are obviously to cover instances where
    transportation of the products takes place.
    
    Bob

    .-1 is exactly what I expected, and exactly why I was surprised. Owing
    to PC trouble I can't confirm the exact rev of the documents I have,
    but they are PDF-format manuals which have almost certainly come off
    the external web in the last month or 3. They may be from the US or
    European pages depending on where and when I got them... I'll be back
    with more info when my PC is sorted...
    
    thanks
    john

	It's all a bit confusing. There are operating and non-operating
	limits. Plus there are various revisions of DEC Standard 102,
	the environmental standard. NPB had chosen to stick with the
	older, more stingent rev E of the altitude portion of the standard.
	The good part is that it doesn't make any difference. I've never 
	known any of NPB's products to fail any rev of the altitude test.

	The DEC Standard 102 web page, tcs.eng.pko.dec.com , notes
	that a new rev of the altitude standard will likely be 
	implmented in the near future. It will be:

		Operating	Rev G Draft (10,000 Ft)
		Non-Operating	Rev G Draft (40,000 Ft)


	Do remember that the max operating ambient temperature is
	decremented as the operating altitude increases.

		Tamb Max = 50C - (1.8C/1000m)*(altitude)

    When you say "altitude test", do we really stick these things in a
    chamber and see how they perform, or is it a careful thermal analysis
    taking into account the reduced convection cooling at higher altitudes?
    
    regards
    john

    Yup...there's a chamber at the Parker Street facility in Maynard.
    Someone like John Thayer can probably tell you more about it.
    He may even have some interesting stories to tell too. :-)
    
    Bob