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Duel Tone Multi Frequency Circuits
Last Updated on: Monday, July 27, 2015 05:14 AM


Links to electronic circuits, electronic schematics, designs for engineers, hobbyists, students & inventors:

AC IR Remote Control -  Self learning PIC16F84 remote control receiver that can be controlled by regular IR remote control. . . 

 

AN-521: Dual Tone Multiple Frequency DTMF -  Application Note. . .  [National Semiconductor]

 

AN-666: DTMF Generation with 3.58 MHz Crystal -  Application Note. . .  [National Semiconductor]

 

Device Control using DTMF -  Controlling devices using switches are common. From a few decades controlling devices using remote control switches like infrared remote control switch, wireless remote control switches, light activated switches are becoming popular. But these technologies have their own limitations. Laser beams are harmful to mankind. . . . 

DTMF Coder Makes Low-Cost Sine-Wave Generator -  10/13/94 EDN Design Idea   A telephone DTMF IC produces, by design, two tones if you connect a single intersection of the IC's 4[x]4 keypad matrix (Fig 1). (Telephones commonly have 3x4 keypads but, unknown to many people, the applicable standard allows for a fourth row of four keys. ) But, if you connect two key inputs at once, the IC produces a single-frequency, low-distortion sine wave. Table 1 lists values for an HM9187 (Winbond Electronics, Santa Clara, CA, (408) 943-6666. (DI #1592] . . .  [by Criscuolo Anna Rita, Labtec Telecommunications, Nichelino, Italy]

DTMF Decoder -  Uses MT8870 DTMF decoder and PIC microcontroller to decode telephone tones. . . . 

 

DTMF Decoder for PC -  Our DTMF decoder can be powered from a 9V battery or from your parallel printer port. It can detect and display all 16 DTMF digits on your computer screen in real-time. The Window's program can be placed in the minimize mode and still detect tones while you use your computer to do other things like Net surfing!!!! We are now in the process of adding an DTMF decoder which will interface to the sound card gameport. . . . 

 

DTMF Decoder with LCD Display -  The DTMF decoder 2 is a useful tool used for decoding DTMF (Dual Tone Multi frequency) generated by telephones. The decoded digits are viewed on a 16x2 LCD screen. . . . 

 

DTMF Generation with 3.58 MHz Crystal -  Application Note. . .  [National Semiconductor]

 

DTMF Generator/Decoder -  . . .  [from Boondog web site]

 

DTMF Products for you -  DTMF decoder can be powered from a 9V battery or from your parallel printer, schematic and windows demo program, design by Schmidt Technologies. . . 

 

DTMF Radio Remote Control -  Here is a circuit of a remote control unit which makes use of the radio frequency signals to control various electrical appliances. This remote control unit has 4 channels which can be easily extended to 12. . . . 

 

DTMF RECEIVER -  Today, most telephone equipment use a DTMF receiver IC. One common DTMF receiver IC is the Motorola MT8870 that is widely used in electronic communications circuits. The MT8870 is an 18-pin IC. It is used in telephones and a variety of other applications. When a proper output is not obtained in projects using this IC, engineers or technicians need to test this IC separately. A quick testing of this IC could save a lot of time in research labs and manufacturing industries of communication instruments. Here’s a small and handy tester circuit for the DTMF IC. . . . 

 

DTMF Tone Decoder -  hears touch tones and displays them as telephone numbers. . .  [Bob Blick's design]

 

Dual Tone Multiple Frequency DTMF -  App Notefirst published04-Nov-1995. . .  [National Semiconductor]

 

Full-duplex doorphone with 3 Wires connection -  a two-way (full-duplex) construction planned for use as doorphone. . . .  [Peter Jakab, Electrical Engineer, Engineer of Informatics]

 

Radio Remote Control using DTMF -  Here is a circuit of a remote control unit which makes use of the radio frequency signals to control various electrical appliances. This remote control unit has 4 channels which can be easily extended to 12. This circuit differs from similar circuits in view of its simplicity and a totally different concept of generating the control signals. . .  [Radioland.net]

 

Remote control using telephone -  Here is a tele-remote circuit which enables switching "on" and "off" of appliances through Telephone lines. The circuit described here can be used to switch up to nine appliances (corresponding to the digits1 through 9 of DTMF the Telephone key-pad). The Telephone can be used to switch. . . 

 

Simulate signals for telecomm tests -  09/11/99 EDN Design Idea   The circuit in Figure 1 is a miniature gadget that is helpful in telecommunication applications. The function of the device is to simulate data flow with predefined patterns and use these patterns to check a cable's or a receiver's functionality. The circuit generates a signal in accordance with alternating-mark-inversion (AMI) code. . .  [by Samuel Kerem, Patton Electronics, Gaithersburg, MD]


Duel Tone Multi Frequency (DTMF) Circuits


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