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Rotory to Touch Tone conversion? Answered

I have a desk phone from the late 60's and I am looking for a circuit wether arduino or basic stamp etc., to convert the pulses to touch tone.  Any ideas?



There would be  a heck of a lot of coding to generate tones in an arduino or stamp directly, or you'd have to mess with additional hardware like the MT8870 chip

Hey Steveastrouk - Thanks for the info. I checked both sites and they are wonderful, the dialgizmo is handy for someone who has no clue as to how to operate a screwdriver, oldphoneworks is great for the purist who wants an old style phone without external hardware hanging around.  Further at $39 you can't beat it for the simplicity. - Foxtrot70

Happy to help ! Took some googling to get a good search !


dredging up an old question, but for the benefit of anyone looking for the solution to this, the new tone library for arduino (which needs to be downloaded and installed separately here: http://code.google.com/p/rogue-code/wiki/ToneLibraryDocumentation ) supports the output of 2 simultaneous tones. With the aid of the appropriate DTMF frequencies, it should be fairly trivial to generate DTMF codes.

Then some code to count the pulses and some phone line inferfacing hardware ( http://brohogan.blogspot.com/2009/12/telephone-interface.html ), and you're set.

There's an Instructable HERE which does the first part - converting the rotary pulses to a number down a serial link.  If you connected the serial to a modem and prefixed it with 'atdt' you should be able to dial.  (You'd have to play around with getting the handset live when when contact was made.)


8 years ago

You can buy DP to DTMF converter for $50-$75 that are straight plug-in hardware, no external power sources are needed.  I don't have a link, but just Google "DP to DTMF converter"  and you'll find a number of places to get one.