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'[OT] tel. call detector'
1999\11\18@112442 by Wagner Lipnharski

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> At 13.39 18/11/99 +0800, you wrote:
> >Hi everyone,
> >
> >        I'm quite new to the list but been lurking for sometime now, so
> pls. be
> >gentle... I'm doing a F84 project that involves the telephone, How can i
> >detect if the called party have answered the call i made ? What control
> >signals does a typical telco uses to supervise the line ?
> >
> >All the best,

Now THAT's easy!!!
Just filter the 17367Hz special tone every telephone sends for half
second when you answer the call... easy huh? the only problem is that no
idiot yet develop this idea, and we still using telephones as it was
invented 5 thousand years ago.  Ok, nobody will replace all telephone
sets in the world, so then use the 1718Hz special tone that a central
telephone exchange send to you when your calling party answers the
phone, what? it is not available also? what a heck? not even a 130
million dollars exchange system can do that? We are really doomed man!

Ok, going back to the caves, take the lion aside, and put few more logs
into the fire to keep reading this email, you just need to "guess" if
phone was answered when the one of the "call progress*" indicators, the
"calling" signal stopped for one of the following reasons:

a) A nuclear explosion just wiped out the calling phone city, or perhaps
the state.
b) The very old phone lines wiring of the calling party just melted with
the ringing voltage, and short circuited.
c) Your phone line was cut out and you can't hear anything else.
d) The calling party answered the phone.

Now, your circuit should decide (by ...guessing) what happened at the
other side.  Isn't ridiculous how simple it would be if the answering
phone just send a "beep" in a special frequency when answering the call?

* There are few chips called "call progress indicator" than can tell you
if the signal at the line means "busy", "calling", "reverse call", and
few others.

Wagner.  (a grumpy person about our jurassic phone system)

1999\11\18@120549 by Gordon Varney

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{Quote hidden}

Wagner,
   Don't worry to much about the antiquated phone system. The internet has
changed that already. Within the next few years all phones will be DSL
(digital subscriber lines) and the analog audio problems with bandwidth and
controls will be lost forever. Then if your phone don't work you will call
an engineer to have it fixed because just like the new automobiles and
mechanics, the technicians won't be able to fix them.

Gordon Varney

1999\11\18@144505 by M. Adam Davis

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Actually, it's a much simpler situation than what you describe:

People don't want to make it easy for machines to call people!  I'm sure
you've had the "Please stay on the line for an important message about
<...>" phone calls.  Fax machines, modems, pagers, etc all send or
receive special tones to communicate with other machines.

There are times where such an action may be desirable, though, such as
an automated alarm system calling an emergency number.  Pagers can be
used more effectively for machine to man alerts (such as servers going
down, etc).

Can anyone else think of a good reason to have such a function that
wouldn't be equally or better served by a special reception machine, or
another form of communication?

-Adam

Borg Answering machine message:
"We are the Borg. Resistance is futile. However we are unable to
assimilate you now. Please leave your name, number, and where you can be
assimilated, and we will assimilate you as soon as possible."

Wagner Lipnharski wrote:
{Quote hidden}

1999\11\18@162015 by paulb

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Wagner Lipnharski wrote:

> Wagner.  (a grumpy person about our jurassic phone system)

 Ahem.  Yeah, we noticed.

 I'm pretty grumpy about OCTEK motherboards right now, since my surgery
machine turned up its toes in a very definite manner Monday lunchtime.
--
 Cheers,
       Paul B.

1999\11\19@052652 by Alan Aldaba

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Hi,

Wagner Lipnharski wrote:

> * There are few chips called "call progress indicator" than can tell you
> if the signal at the line means "busy", "calling", "reverse call", and
> few others.

       Where can i find out more about these chips, can you pls. specify some
part numbers and manufacturer ? I think you're much fortunate, here in
the Philippines, our telco doesn't have a caller id service and our
access speed is limited to 33.6 K....

all the best,

Alan

1999\11\19@092742 by Wagner Lipnharski

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Alan Aldaba wrote:
>
> Hi,
>
> Wagner Lipnharski wrote:
>
> > * There are few chips called "call progress indicator" than can tell you
> > if the signal at the line means "busy", "calling", "reverse call", and
> > few others.
>
>         Where can i find out more about these chips, can you pls. specify some
> part numbers and manufacturer ? I think you're much fortunate, here in
> the Philippines, our telco doesn't have a caller id service and our
> access speed is limited to 33.6 K....
>
> all the best,
>
> Alan

Hey Alan, I am sending you this post by a V90 modem operating at 26400
bps, since this is the highest speed I can get from Bellsouth here in
Orlando, believe me or not.

Teltone has several of those chips, for example, the M-980, 1, 2 or 4
Here goes:
www.teltone.com/telecom_ics/mini/980-02_mini.html
www.teltone.com/telecom_ics/mini/984-01_mini.html
www.teltone.com/telecom_ics/mini/982-02_mini.html
www.teltone.com/telecom_ics/mini/982-01_mini.html
http://www.teltone.com/telecom_ics/mini/981-01_mini.html

1999\11\20@075401 by Alan Aldaba

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Wagner Lipnharski wrote:

> Teltone has several of those chips, for example, the M-980, 1, 2 or 4
> Here goes:
> www.teltone.com/telecom_ics/mini/980-02_mini.html
> www.teltone.com/telecom_ics/mini/984-01_mini.html
> www.teltone.com/telecom_ics/mini/982-02_mini.html
> www.teltone.com/telecom_ics/mini/982-01_mini.html
> http://www.teltone.com/telecom_ics/mini/981-01_mini.html

Thanks, Wagner

Regards,

       Alan

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