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What do the numbers mean


What do the numbers mean

No, nothing X-files like.

Having purchased a Zyxel Prestige 643 as my hardware of choice long over a year ago, I have never looked back.

There are a few bits that I don't like about it, but I can live without them, as they can often be done using software, or nly get used on a very limtied basis.

One of the things that has allways confused me is the output given for noise levels.


relative capacity occupation: 39%
noise margin upstream: 25.0 db
output power downstream: 20.0 dbm
attenuation upstream: 18.5 db


relative capacity occupation: 10%
noise margin downstream: 30.5 db
output power upstream: 10.0 dbm
attenuation downstream: 32.5 db

I know I am well within the bondries of getting 1mb, but can anybody explain the figures a little more.
Community Veteran
Posts: 6,983
Thanks: 8
Registered: 10-04-2007

What do the numbers mean

Hi Phil
Dont understand the relative capacity occupation: 39% but the others I can perhaps enlighten you on.

noise margin upstream: 25.0 db
This is telling you that the upstream signal is 25db higher than the ambient noise level.

output power downstream: 20.0 dbm
This is the power transmitted in the downstream path relative to one milliwatt, so the actual power is 100 milliwatts.

attenuation upstream: 18.5 db This is the measure of the line loss in the upstream direction so the signal is being attenuated by 18.5db.
in reality this means that about 1/70th of the original signal gets to the other end.
(Every 3 db step is a halving of the original power so 3db=1/2 6db=1/4 9db=1/8th and so on)

Hope this clears some of the figures up?
Posts: 3,835
Registered: 05-04-2007

What do the numbers mean

They also mean you should be fine with 1MB on the line!

What do the numbers mean

Shut it Mr Salesman! :lol:

My plans are allready in place. Once I have this damned office onto the new service (and my referal goes up), I plan on an upgrade.

I just want the trial out of the way. Allthough pretty much a complete process now, I prefer to know things will work.