ADSL Max - do telephones have any effect?

[FunkyT]

It has been suggested to me that telephone use can have an adverse effect on ADSL. I was just wondering if there would be any benefit in diverting my phones for the during of ADSL Max training?

[emul8]

Then it was a rubbish suggestion the information is transmited on two different frequencys.
The only problems your going to get are if you dont have a filter fitted and that will efect the voice line not the ADSL.

[FunkyT]

Whilst they operate a different frequencies there is bound to be a relationship between the ADSL and Voice signal.

The filter removes most of noise, however, there can be issues with noise generated by the phone, and stray frequencies. Although it's probably not as much as I initially thought. Good filters will as you say keep most of it out but as for being no crosstalk at all then I would very much doubt it.

There are issues with a "high bearer" whereby the ADSL signal only operates when the phone is off the hook. BT know of this problem, so there is a relationship between voice and the ADSL signal.

[PriestJPN]

Some digital cordless phones can cause problems with ADSL usage...

[Funkstar]

How is a digital cordless phone any different to any other phone?

Sure they can interfere with wireless networking as they are on the same frequency, but that isn't going to cause problems with ADSL, just your wireless.

[PriestJPN]

Sadly, not true - I do see the logic behind your thinking, but as someone who has worked for an ISP I've seen multiple examples (we're talking 20+) of users who had no ADSL connections with the digital cordless phone plugged in.

Unplug it and it works. 100% undeniable fact.

[emul8]

Thats weird and by the numbers quoted rare
I have two cordless phones both hooked up to the same line as my adsl.
I often make calls wilst downloading or browsing to no noticeable effect to my connection.
I did notice when i pick up the phone downstairs the radio goes quiet.

[Funkstar]

so unpluggin the phone solved it. what about just turning off the handset?

a dodgy or badly designed base unit has nothing to do with it being cordless. the same would happen if the base unit electronics were used in a corded phone

[PriestJPN]

The key word here is DIGITAL. You don't get the problem with the old type cordless phones.

[Funkstar]

i still fail to see how a digital cordless phone can interfere with an ADSL connection. If that is the case then 802.11b/g/n would also interfere as they are the same frequency, along with bluetooth and microwaves.

If is isn't to do with the 2.4ghz spectrum then i still maintain it is dodgy/out-of-spec base station that would cause interference, if it was cordless or not.

[PriestJPN]

I can't tell you exactly why it happens; I suspect that manufacturers of the phones providing slightly out-of-spec equipment (like you say above) to users despite having BT approval. I do know that it is to do with signal strength and the lack thereof.

After working with BT (Business to business, not the guys you call for residential problems) and Virgin, TescoNet and NTL Freedom, this is a problem that did rear its ugly head now and again. Things that should make sense often don't when you have so many random factors - line length and quality, differing equipment, etc. Concerning 2.4Ghz, wireless or whatever; this is not where the problem stems from.

If I don't know much about a subject, I'll be the first to admit it but please don't make it sound as if what I say is wrong just because it doesn't make sense. I'm in work now and after doing a quick poll, there's at least one guy in the office who has actually had this problem (not that it means much to anyone reading this).

[Stoo]

There's a bunch of stuff that BT say can muller your ADSL connection, everything from CB radios, microwaves, central heating systems, to christmas lights, etc..

Nothing to do with their phone lines being a bundle of crap, and most of the Max implementation being bodged then..

*mutters*

[emul8]

If I don't know much about a subject, I'll be the first to admit it but please don't make it sound as if what I say is wrong just because it doesn't make sense. I'm in work now and after doing a quick poll, there's at least one guy in the office who has actually had this problem (not that it means much to anyone reading this).

Hey PriestJPN I don't think anybody is doubting you Or your knowledge
It just seems quite bizarre how this can happen and I for one would like to know what factors would contribute to any kind of adsl interference.

[slugs]

the speed you get is in direct proportion to the snr of the telephone line. therefore if you connect more devices to the line or install equipment that is operating outside the normal freqency ranges it will cause issues.

i would wire your adsl directly into the nte box if that makes the performance any better.

ive seen issues with fax machines and pdq machines causing the line to run slower but not digital telephones on the devices that caused issues we needed to put two microfilters on to clean the signals up

[Nat101]

Judging by the fact that switching to decent microfilters boosted my line sync by 2Mb/s, I'd say yes, phones do effect performance. Whether some modems are more susceptible to frequency leakage than others remains to be seen...

[Funkstar]

If by replacing the microfilter to a with a better quality one increased the poerformance of the line then i would be blaming the old microfilter, not the phone. With a bad microfilter any phone can cause problems.

Yeah i know it's pedantic, but i'm offshore and really bored