DTMF outputs

I know that it is possible to output a tone from an Arduino output, has anybody written a library that would output a DTMF (Dual-Tone Multi-Frequency or “Touch Tone”) ? The Basic Stamp compiler had this function built in and it was very good for remote control over a radio link.

I read in hack-a-day a couple months ago about a robot cobbled together with an Android G1 headset and an Arduino. The control interface between the two was DTMF (DFMT?).

Here’s the link:

Also, soooo cute.

There was a nice I2C chip for DTMF - Philips PCD3312C, but I beleive it’s discontinued.

However there are DTMF receiver, generator and transciever chips like the HT9170B. I’ve haven’t used them yet, but you can check them out at http://www.futurlec.com/index.shtml. Just type DTMF in the search box.

Futurlec to the rescue! Those Holtec chips are slick. Thanks!

Are the Holtec devices current manufacture? The receiver looks very similar to an 8870 (but I haven’t compared datasheets).