AVR-Chat

Hi!
To sense the logic line is very simple with a MCu or a
couple of Smith Trigger buffers.

You only need know first the Vcc values for each state
of the line, 48Vdc is ready to use less than this is
in use 15-4Vcc, and more than 48V is ringing.

You can sense too if you are directly connected to a
POTS line from you service provider, becose if you are
using a phone central the VCC and some logic of the
line is descarted from the Telco central.

You can use the tone inside of the line to sense using
a Voice detector (Vox), if the tone of the line is
ringing, ocuped or not available, this is the way the
mos modem use to know the state of each call.

best regards
Frank

 --- Stefan Trethan <stefan_trethan@gmx.at> escribió: 
> 
> On Tue, 1 Feb 2005 03:49:56 -0800 (PST), Shibu
> Krishnan  
> <shibunellad@yahoo.com> wrote:
> 
> >
> > hi folks
> > pls respond to my query. i hv posted 4 quiries so
> far.
> > but no reply. i am beginner in using MCUs
> > i am doing a project on IVRS. am in the initial
> step.
> > i need some SLIC for ring detection and off hook.
> can
> > anybody suggest the best and affordable ic which
> can
> > be  interfaced with AVR 8515 MCU.
> > thanking u.
> > shibu
> 
> 
> Shibu,
> perhaps you would get more replies if you used a
> proper Subject.
> Remember most don't read something like "Digest
> 920".
> 
> As for your problem, i don't know what SLIC means,
> but i know there are  
> working circuits out there to detect ring and off
> hook, which can be built  
> with discrete components and connected to IO pins of
> your Atmel. Google  
> for "phone in use schematic" .
> You will then find plenty of stuff like this:
>
<http://www.ee.washington.edu/circuit_archive/circuits/F_ASCII_Schem_Tel.html>
> 
> ST
> 
> 
>  
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> 
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> 
>  
> 
> 
> 
>  

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