RE: phone tones and Keith Doxey's help?

["Steve Morgan" <smorgo@xxxxxxxxxxxxx>]

Would a K-Break cause problems with ADSL, do you think?

Steve

> -----Original Message-----
> From: ukha_d@xxxxxxx [mailto:ukha_d@xxxxxxx]
> On Behalf Of Keith Doxey
> Sent: 19 August 2006 23:26
> To: ukha_d@xxxxxxx
> Subject: RE: [ukha_d] phone tones and Keith Doxey's help?
>
> I concur that it is NU tone.
>
> Exchanges now give the called subscriber Number Unobtainable
> Tone (NU Tone) if the incoming caller clears and the handset
> is not replaced. This disappears after a period of time to be
> replaced by the "howler" which is a two tone noise that
> increases in volume to alert someone to the handset not being
> replaced properly.
>
> Description of tones can be found here
> http://www-users.cs.york.ac.uk/~fisher/telecom/tones/
>
> As it is actually 10 years since I worked on phone lines I
> cant be sure of the exact conditions that are now present on
> phone lines but imeadiately on termination of a call there
> was a momentary break in the line known as the "K break".
> (Name derived from the relays used in early strowger exchanges.
> Each line had dedicated LR & K relays but shared the other
> exchange equipment with many other lines)
>
> Answering machines detect this condition and stop recording.
> I had an answering machine that worked perfectly on an
> exchange line but when used on an extension on my Pentara it
> used to record continuously as it didnt see the line break.
>
> Out of interest... is this a BT line or some other provider ?
>
> ***
> From http://www.dt4u.com/dtsystems/dialupfaqnew.php
>
> "Why will my Dialup not Clear down when I hang up (Auto Mode)
>
> Some exchanges notably NTL have a non standard cleardown
> sequence where the industry standard K break signal is
> missing. The only work around for this problem is to switch
> off your Dialup unit at the conclusion of the program.
> If you wire up the mains as shown elsewhere, this will happen
> automatically - whenever the sound system is switched off."
> ***
>
> Whilst Googling for info on the "K-Break" I came across
this....
>
> http://www.ukha-archive.com/ml/ukhad/2001-mar/msg00924.html
>
> ... written by some bloke called Keith Doxey, whoever he may be!
>
> ***
> "It could be the exchange.
>
> There is a period of time called the "Disconnect Clear Time"
> when the exchange line is physically removed to allow
> equipment to fully disconnect from the call. This is the
> modern digital equivalent of what used to be known as the "K
> Break" on strowger exchanges. Many answering machines used to
> make use of this to stop recording if the caller hung up.
>
> Some exchanges have this disabled as some modern PBX's
> interpret the reconnection of power to the line as a new
> incoming call and will start a phantom ring that stops after
> a couple of seconds.
>
> Just another useless bit of trivia for you :-)
>
> If it is causing you real problems you could try calling
> faults and getting the disconnect Clear Time set to Zero."
> ***
>
> Which has just kicked the old grey matter into gear again. It
> could be that if you do have a BT line, it might have been
> set to have Zero or insuficiently long "Disconnect Clear
> Time" for the Comfort to release. Might be worth asking
> Comfort Tech Support if there are different specs for the
> Disconnect clear on Comfort 2.
>
> HTH
>
> Keith