I was hoping to create a cheap security system by connecting an Arduino to the phone line output of a base station.
Since the base station should call a phone number if the alarm is tripped I wouldn't have to do much hardware hacking so long as I can read/parse the output from the base station.
My question is can I read serial output from a phone line like this?
-
1Serial connection over a phone line is done using a "modem" - you can probably still find an RS232 external one on a surplus site for which you will need a serial level shifter (with implicit inversion). You may also be able to find a new module for embedded use, perhaps even one with logic level serial. Most sophisticated enough to use the AT command set can dial.Chris Stratton– Chris Stratton2015年01月02日 15:01:52 +00:00Commented Jan 2, 2015 at 15:01
-
These days you can find TTL modems, removing the need to deal with RS-232.Ignacio Vazquez-Abrams– Ignacio Vazquez-Abrams2015年01月02日 17:16:21 +00:00Commented Jan 2, 2015 at 17:16
1 Answer 1
Phone lines run off of the RS-232 telecommunications protocol which can run off -25v to 25v, which would completely destroy your Arduino. Luckily there is an IC made to help you with that. You can use the MAX3232 IC to convert RS-232 to TTL 5v or 3.3v (Same chip can do either). Look at providers like Digikey for just the chip or you can get a breakout from providers like SparkFun.
TL;DR Yes, but you need a special IC to not fry your Arduino.