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will this interfere with ordinary telephone calls?

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not if your filters are all present and correct.

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not if your filters are all present and correct.

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Some cheaper filters don't regenerate the ring wire, but instead just pass it straight through.

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Some cheaper filters don't regenerate the ring wire, but instead just pass it straight through.

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that's covered by the "correct" bit - such filters don't comply with the BT SIN requirements.

Getting a 2uF non-electrolytic capacitor into something the size of two sugar cubes can be a challenge in the cheaper filters, so they either don't fit one at all, or they fit a lower value capacitor

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such filters don't comply with the BT SIN requirements.

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Sorry, but I just checked SIN346 and it allows for the bell wire to be filtered or recreated.

Edited by cahaddras (Sun 25-Mar-07 11:57:08)

Not wanting to drift too far off thread but would it be possible for one of us to make up a super-dooper bandpass filter for this purpose, given unlimited space?
Mike.

but the SIN does not allow for it to "but instead just pass it straight through" as you described.

Edit: granted a filtered ring wire would comply but need the ring wire to work for many phones, are there any filtered ring wire examples in the wild ?

Edited by yarwell (Sun 25-Mar-07 12:16:51)

do you have the gear to assess the effectiveness of filters ?

Scope and audio sig genny.
That should do?

Guess there are some circuits out there for the ultimate filter?

Mike.

have you looked at
http://www.adslnation.com/support/filters.php
http://www.sinet.bt.com/346v2p6.pdf

It would be interesting to see what your scope sees on a ring wire, for example, as well as on an incoming pair without the aDSL on.

Measuring the ADSL signal levels on the phone side of a microfilter would also be interesting to see if there is a performance variation between designs.