Is anyone know what is the equivalent IC of UM91214B and KT3170??UM91214B is dual tone multi frequency(DTMF) generator.KT3170 is a DTMF to BCD converter. What is the manufacturer of those IC? Where can I get them? Thank you.
UM...is from United Microeledtronics Corp.,KT.. from Samsung,but discontinued. For DTMF decoding i recommend MT8870 from Zarlink.
UM91214 have stand-alone feature:the mixed tone+pulse redial. If You don`t need these function, use MT8880.
Hi,
Connect the switch inputs of UM91214 to the data pins of your parallel port. Give proper 1 and 0 signals to these pins as if you are simulating a matrix key-pad. Thats it. Nothing more is required.
u mean if i want row 1 and col 1 dtmf tone,
i simply put 1 on both the row 1 and col 1 pin ?
u sure. i read somewhere u r supposed to short the
required row and col pins. this wud mean that some current flows
into and out of the pins. wont that blow up the parallel port ?
You can make this only with optocouplers or analog switches. When a button pressed on a crosspoint, started a scanning, (outputs producing shifted phase square wawe) and this signal go to input.