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Berkeley, CA

Test fusion modem at NID?

I'm thinking I should test out my Fusion modem at the NID to see if lousy wiring inside the house is taking a bite out of my speed. Can anyone advise me on a few questions:

1. What measurements should I look at to compare performance between the NID and my inside jack? Rate, Max Rate, Noise Margin, Attenuation?
2. After I hook up the modem at the NID, will those data update immediately on the gateway.sonic.net screen? Or does it take some hours, overnight, other?
3. What is the modem statistic that compares to Sonic's speed-distance chart?


Sunnyvale, CA

1.) Since it seems you are doing this for performance reasons and not for the purpose of troubleshooting a problematic connection you already list the 3 most important factors: sync rate, attenuation and snr (signal to noise ratio or noise margin). Max attainable rate is really only useful if you have an ISP that limits the sync rate for profit reasons (speed tiers).

2.) When you power on the modem it will start a line test together with the DSLAM (the device on the Sonic end of the connection). This test determines which of the theoretically possible transmit and receive frequencies are fully or partially usable to transmit data and which ones have too much interference or too much attenuation to be usable. The sum of the number of bits that can be transmitted on the usable frequencies determines the data transfer rate (sync rate). Generally this rate is a little higher when you first turn on the modem then after running it for some time. The main reason for that is that sporadic interference may not be present at the time you first turn on the modem and only show up during use later on. This results in some bits that were initially thought of to be usable to be turned of later on because of too many errors (which in turn results in the data transfer rate being reduced).

To get a meaningful comparison do both the NID and the inside test after the same amount of time after turning on the modem (e.g. after 10 minutes in both cases).

3.) I'm not sure I understand the question. I'm tempted to say "none", since the statistics in the modem will not give you the distance from the CO. Of all the statistics parameters, attenuation is the one most effected by the length of the dsl line however other factors (wire gauge, number and quality of splices/terminations) play a role as well. The sync rate (data transfer rate including protocol overheads) is the speed in the speed-distance chart.
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Berkeley, CA

1 edit

Thanks leibold, that's really helpful!