Telephone line connection [Caller ID project]

[2f1c]

hi everbody,

i started a little project , which is about building a caller id circuit around an atmel 8bit mcu.

i don't plan to use any decoder chip nor module for that, the demodulation should be done on the microcontroller.

i found somewhere a good software based fsk demodulator for atmega8 i believe, though i don't think that the software part is that difficult (worst case : i use two mcu's )

i'm in the process of designing this thingy, and first started with the connection to the telephone line.

For debugging puropses , i plan to connect the phone line to the sound card so i could pick up easily any signals flowing through and hopefully do some digital processing in matlab

what do you advise me , specially regarding ratings , and protections i should use to connect my phone line to the sound card ?

comments / ideas / suggestions are welcome.

thanks in advance.
--
tewfik

 

[crutschow]

Where are you located? Phones are different depending upon the country.

 

[2f1c]

thanks for the reply,

i am in algeria, and i believe the line is european compliant.