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wellsman 发表于 2012-8-18 18:45 
高手啊!
我和Telecom的客服联系时,他们说是5公里左右,但他们说这不是很远的距离!
有解决的办法么,除 ...
再來附上一個轉貼 有關 SNR 與 Line Attenuation :-
SN Margin
(AKA Signal to Noise Margin or Signal to Noise Ratio)
This is the relative strength of the DSL signal to noise ratio - the higher the number the better for this measurement. 6dB is generally the lowest dB manufacturers specify in order for the modem to be able to sync. In some instances interleaving can help raise the noise margin to an acceptable level. Generally speaking, as overall bandwidth increases, your signal to noise ratio decreases.
6dB or below is bad and will experience no sync or intermittent sync problems
7dB-10dB is fair but does not leave much room for variances in conditions
11dB-20dB is good with little or no sync problems (but see note below)
20db or above is bad, this occurs when the end-user is too close to the phone exchange. If this occurs the user may end up with alot of DSL connections. To reduce this we can place the user on a low noise profile, which does sometimes resolve the issue.
Note: there may be short term bursts of noise on your line that may drop the margin, but due to the sampling time of the management utility in your modem/router, will not show up in the figures.
Line Attenuation
This is a measure of how much the signal has degraded between the DSLAM and your modem/router, and is largely a function of the distance from the exchange (bigger distances mean higher attenuation). Maximum signal loss recommendation is usually about 60dB. The lower the dB the better for this measurement.
20dB and below is outstanding
20dB-30dB is excellent
30dB-40dB is very good
40dB-50dB is good
50dB-60dB is poor and may experience connectivity issues
60dB or above is bad and will experience connectivity issues
Note: From a user perspective, there very little you can do to change the line attenuation of your current connection.
上面資料的原址:-
http://www.gpforums.co.nz/thread/250050/?s= |
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