Looking for Answer. Connect Two Arduino's over two FRS or CELL Audio

Greetings,
I am wanting to take two "arduino duemilanove" one being the Master and the other(s) being a slave and then use
either two cell phone audio jacks (Basicly I dial the other phone, a person answers and then plugs in his Arduino) to
connect for communication.

#1. Is this possible

#2. Has anyone done this, if so where can i start or get your code or direction on where to go next..

Thanks in advance.

  1. Yes, almost anything is possible but you won't get it for reasonable costs. Your project means modulating your data on an audio layer which is then digitized using lossy compression, transmitted and brought back to analog audio again. Although this is possible (and was done back in the old analog mobile communication time) it needs specialized hardware not easy to get nowadays.

  2. If anyone has done this, it's not just a bit of code but at least some additional hardware. You haven't specified your speed requirements. If 1 Baud is enough you might get acceptable results with just some sinus curves sent using AM modulation but if you expect 1kBaud and above you should look for another solution.

Your project means modulating your data on an audio layer which is then digitized using lossy compression, transmitted and brought back to analog audio again.

The information in the Arduino can be represented by hexadecimal numbers. The DTMF (aka 'TouchTone) standard has 16 tone pairs which means that the information in his 'Master' Arduino can be converted, on a one-for-one basis, into DTMF tones which the phone or radio can easily transmit. The 'Slave' Arduino could then convert the received DTMF tones back into hexadecimal numbers.

Don