[Gllug] ADSL problem

Chris Bell chrisbell at overview.demon.co.uk
Fri Feb 25 11:59:37 UTC 2005


On Fri 25 Feb, t.clarke wrote:
> 

> Normally 'ringing' is supplied from the exchange as 50V (or thereabouts) AC
> with enough juice (a) to give you a jolt if you touch the wires and (b) to
> drive the ringer on one of the older phones.  I believe the modern phones
> using electronic ring tones do not use the AC to drive the ringing directly
> but merely detect it and then generate the ringing internally.  Thus, spurious
> AC of any sort on the line, I believe, can cause the phone to ring.
> 
> Tim

   The old phones did use medium voltage 17Hz ringing, and line-drop
dialling, but modern phones respond to higher frequency signal tones similar
to the dial tones from the keypad. The ADSL carrier will not be recognised
and decoded but can cause continuous ringing.

-- 
Chris Bell

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