Jeffrey,
I'm not sure what are looking for ("what is your interpretation of the
maximum sound level limits?).
By your comment "we are strictly CO, -48VDC @ 110A" I am assuming your
equipment would be located within a line-up with other equipment. Therefore
you would have to meet the 60dBA
level. You can argue that your equipment also can be placed in other
categories, but then you
are limiting the deployment of your equipment. RBOCs don't like those
restrictions. With space being tight at many COs, who knows (they don't)
where 'exactly' they will put your equipment.
As for "What are the RBOCs and other Telcos looking for ?", read Section 1.1
'Purpose and Scope" of GR-63-CORE. " . . . spatial and environmental
criteria for all new telecommunications equipment systems used, including
colloacted equipment, in COs and other telephone buildings of a Bellcore
Client Company." Additionally, ""Compliance with these requirments may
increase netwrok robustness, simplify building-environment interfaces, and
help make the planning and engineering of COs simpler and more economical."
Also take note that the RBOCs each may have additional (or a variation of)
requirments
that you may need to look into.
Of course, this is customer driven. But if you want to do business with
them, you have to
meet these specs. Otherwise they will choose a comparable product, even if
it's more expensive,
that does indeed meet these specs.
When I did the testing at my former employer, we did measure sound pressure,
as per the procesure in section 5.6.
John A. Juhasz
Compliance Engr.
Fiber Options, Inc.
Bohemia, NY 11716 USA
-----Original Message-----
From: Collins, Jeffrey [mailto:[email protected]]
Sent: Monday, February 14, 2000 1:33 PM
To: '[email protected]'
Subject: NEBS Question: Acoustics and Sound Power (GR63)
Colleagues,
What is your interpretation of the maximum sound level limits? The four
classifications of equipment are vague in Table 4-12. We are strictly CO,
-48VDC @ 110A.
I can find a good argument to classify our product into 3 of the four
categories. What are your experiences with this? Obviously, NEBS is a
customer driven requirement so what are the RBOC's and other Telco's looking
for?
On another issue, is anyone taking their acoustic measurements in sound
power instead of sound pressure? I recall that Bellcore was going to
implement this change in the near future.
I also believe there is an ISO requirement in Europe (ISO 7779) that
requires acoustic measurements in sound power. Is any one testing to these
requirements?
Can you provide examples for each Acoustic category?
Equipment Types
Sound Level Examples
Equipment to be located in power rooms 83 dBa
?
The maintenance control center of an equipment 65 dBa
?
system where normal speech and telephone
communications are required.
An individual equipment frame that maybe located 60 dBa
?
in a lineup with other equipment.
All other equipment.
75 dBa ?
Thanks in advance,
Jeff Collins
MTS, Principal Compliance Engineer
Ciena Core Switching Division
[email protected]
1-408-865-6406, Fax 1-408-865-6291
www.ciena.com
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