hi all
i make project that can detect DTMF/SCK by sm8223 IC,but i want when i recieve call make hook-off to send some command by AVR controller (mega16),
is there method that i can make hook-off ?
thanks alot
hi all
i make project that can detect DTMF/SCK by sm8223 IC,but i want when i recieve call make hook-off to send some command by AVR controller (mega16),
is there method that i can make hook-off ?
thanks alot
Last edited by alitex; 16th October 2009 at 01:20 PM.
Connect a 470 ohm resistor across the line to take it 'off-hook'
A 470 ohm resistor across a North American telephone line will dissipate about only 0.21W which is not a lot. Use a 0.5W resistor in opean air and it will be fairly warm, not hot.
Uncle $crooge
Different languages are strange.
A can of beer "opens", not a phone line.
A phone line goes "off hook".
If a can of beer goes off hook then you are plastered and should not drink any more beer.
But many weird things happen in Syria? Like hardly any alcohol in beer?
Uncle $crooge
Your country is very strange:
No beer.
Extremely high telephone line current.
I won't talk about your religion (Muslim?).
250mA in 680 ohms produces 42.5W which will quickly smoke a 4W resistor. Maybe the current is only 25mA.
Current is measured in series with the load, not "across" the load.
Uncle $crooge