DTMF stands for dual tone multiple frequency. DTMF is a term which used in telephone industry. When any key on telephone or mobile phone is pressed one tone is generated and it is audible which is nothing but a DTMF tone. To decode DTMF tone from mobile phone we need MT8870 DTMF decoder IC, 3.5mm male and female connector.
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.