DTMF ic for keypad (radio mic upgrade)

I have one. It's handy for HT's that don't have DTMF pads. However, I prefer to use a digital voice recorder.

I have pre-recorded tracks of my favorite repeater control codes that I play into the microphone. For recording the DTMF tones, I just use a dialer or ordinary phone played through the earpiece. I also have the external mic and speaker from the voice recorder wired into a pair of 3.5mm jacks on the radio, which also gives me an instant replay and long term recording feature.

You can also have your computah generate tones using various programs (bottom of page) or a dedicated circuit board:

There are more. Search Google for "DTMF encoder".

It's also fairly easy to make one with a microcontroller, essentially by using a pair of DDS generators. Atmel has an app note on it at . I built one a while back out of curiosity and it seemed to work pretty well. The general technique is adaptable to other uC families, of course.

Hosting the DTMF generator on a micro opens up the possibility of making a "smart device," saving a few keystrokes and reducing errors.

On 2/12/2009 10:07 PM Jeff Liebermann spake thus:

I downloaded this, hoping to play with it (I'm actually interested in seeing if I can approximate the old "Jeopardy!" sounds that they used to play when setting up the board, which I believe were DTMF tones). But it errors out when I run it ("Run-time error '-2147467259 (80004005)': Automation error/Unspecified error"). Win2K Pro, SP3. Know of any problems with this app?

I just downloaded a fresh copy and installed it on a clean computah. XP Home SP3. Installs and runs fine. I do have a W2K machine at home that I can try. There's only one version 1.0.0.0 so I don't think it's an update issue. I couldn't find any requirments for libraries (.NET, JAVA, Visual Basic, etc). Sorry, no clue why it won't run. The error seems quite common:

but none of the hits seem to have anything to do with the problem. My guess(tm) is that some Windoze library is out of date, corrupted, trashed, or missing. Try: (select "custom") and see what it wants to update.

You might also try doing a fast scan for malware and such. Download, install, and update the free version of MalwareBytes:

The "fast scan" is quite quick and catches lots of oddities.

I also have a DTMF encoder program that I wrote perhaps 15 years ago in Borland Turbo Pascal. I'll do the world a favor and leave it buried. I'm a terrible programmer.

There are other DTMF generators around. Google is your friend. This one should work if you have JAVA installed. Give it time to load:

I have a couple old Visual Basic projects that I found a couple years ago, but never used. As it happens, I just removed VB from my computer in preparation for moving to a new PC. I should be able to compile them in a few days, If you're willing to wait, I can send the executables to you when I get my new PC on line and all my software installed.