DTMF Tone Grabber Kit

DTMF Tone Grabber Kit

The kit will detect DTMF tones from a telephone line or via an onboard microphone and display them on a 16 character, single line display. Up to 32 numbers can be displayed by scrolling the display left and right. There is also a serial output for sending the detected tones to a PC. The kit will not detect numbers dialed using pulse dialing.

The kit is controlled by an Atmel 89C2051 micro controller (source code not supplied nor available).


  • Mic or Phone Input via switch.
  • Operating voltage 9-12VDC
  • Displays up to 16 digits, stores up to 32 digits.
  • Dimensions: 3-3/4"W x 2-1/4"L x 1"D.

DTMF Tone Grabber Kit Reviews:

  • --> This kit was a real bargain and no parts were missing.

    It worked the first time I turned it on.To bad I don't need another.

    George Warner



    1. The kit arrived on time.

    2. Nothing looks shoddy or flimsy; feels like quality parts.

    3. Instructions are clear. (There is a section showing the recommended installation order and all parts are labeled on the PCBOARD.)

    4. Handy "heads up" details and tips.

    5. Kit has two input options that you select via an on board switch: phone line or built in microphone.

    6. Cool LCD and serial out which I will use to connect with to PC.



    1. The install list did not mention the diode. (Minor point since the PCBOARD clearly shows where the diode should be placed.)

    2. Had to deduce/guess the orientation of the two socketed ICs. (Pin 1 is not labeled on the PCBOARD and the photo referenced in the instructions did not help. Deduced that pin 1 is upper left corner of each socket. Felt lucky and was.)



    Had everything put together and tested in less than three hours. I did not rush. It works! Good value!