ADSL speeds

eccerr0r · Posted: Sun Jan 22, 2017 2:42 am Post subject:

And in the US, most of them at least in the past have sold fixed rates in order to have room for upselling.

DSL however is being out-competed by cable, so they were likewise forced in some instances to switch over to "fast as possible" and give bandwidth limits. Plus they won't have to worry about QoS questions like "my DSL is only 3Mbit but you said 20Mbit"...
Before they'd have to send out a technician to try to diagnose the line. Now it's your fault...
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grant123 · l33t Joined: 23 Mar 2005 Posts: 990

NeddySeagoon · Posted: Sun Jan 22, 2017 9:11 pm Post subject:

grant123,

Eww ... the manual I found is dated July 2004.
That's probably ADSL at that age, not ADSL2+. However if your ISP only provides ADSL, there is no point in you getting an ADSL2+ modem because it won't go any faster.

Cheap microfilters are a bandwidth killer. They come in two mechanical constructions. A small box with a pigtail, or a single self contained 'doofer' that plugs into the phone socket. The latter are a waste of money - there isn't enough room to put a decent filter in that space. Those are just illustrations of what to look out for. You get what yo pay for. Its worth paying the extra for 'Active Microfilters'

Its easy to test but to avoid outcry from other family members, you might want to wait until you are home alone.
On the router, bring up the line stats page and make a note of the Signal to Noise Ratio and down stream data rate.
Now go around the house and unplug all the microfilters from the telephone jacks, so only the router is left connected.
What happened to the Signal to Noise Ratio and down stream data rate now everything is disconnected?
The change is due to the microfilters not loading the DSL signal. That gives you some idea of the best that you can achieve.
You may want to power cycle the router to force it in reconnect to the exchange.

Also, microfilters fail from time to time. Sometimes its not easy to detect. The failure mode just reduces the ADSL bandwidth.
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NeddySeagoon

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those that have never had a hard drive fail.

grant123 · l33t Joined: 23 Mar 2005 Posts: 990

This page claims the Westell 6100 supports ADSL2+:

https://www.amazon.com/Westell-6100-ADSL2-Modem-Router/dp/B000QPPY0A

This looks to be the highest rated DSL filter on Amazon:

https://www.amazon.com/In-line-DSL-Filter-w-Splitter/dp/B003807GK6

Should that one be OK?

NeddySeagoon · Posted: Mon Jan 23, 2017 7:47 pm Post subject:

grant123,

It appears that the Westell 6100 has changed over the years. The one in your link certainly provides ADSL2+
Ordinary ADSL can deliver up to 8Mbit/sec. ADSL2+ is up to about 20Mbit but the extra 12Mbit is carried on higher frequencies (shorter range) that the original ADSL signal.
In other words, ADSL2+ won't help unless you can max out ADSL. Also, your ISP has to provide ADSL2+ at their end.

Don't be in a hurry to replace your microfilters. Do the test first.
The router alone does not need a filter.
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NeddySeagoon

Computer users fall into two groups:-
those that do backups
those that have never had a hard drive fail.

grant123 · l33t Joined: 23 Mar 2005 Posts: 990

That was a crazy week. I will get those line stats this coming week.

Filters are so cheap I think it's worth trying a new one. Should it be better to get one that plugs into both the phone and modem like this:

https://www.amazon.com/In-line-DSL-Filter-w-Splitter/dp/B003807GK6

or one that only plugs into the phone? This is for an office and there's only one phone.

NeddySeagoon · Posted: Sun Jan 29, 2017 2:54 pm Post subject:

grant123,

The modem does not need a splitter. The phone line is wired directly to to modem.

The way ADSL over the phone line works is the line is split into a number of 4kHz channels.
Baseband, 0-4kHz carries phone voice.
Then the are a couple of unused channels, so the filter does not need to be perfect.
Next are the ADSL uplink channels.
Above the uplink channels are the downlink channels. How many downlink channels you can receive depends on lots of things.
Line length, noise ... the higher frequencies vanish first.

Test with only the modem connected. All non modem devices need to be filtered somehow.
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Regards,

NeddySeagoon

Computer users fall into two groups:-
those that do backups
those that have never had a hard drive fail.