DTMF generator

still has some products, but most are tagged "Not for new design". It looks like they have already dropped over 75% of the Teletone chips.

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Check the bgmicro catalog page below.

What do people use these days? Maybe a micro with a D/A?

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Try

There seems to be no end to the creative and tasty ways you can enjoy SPAM.

But they have to exist, because every single phone (landline and cordless) and any other device that has to dial would have one.

Surely you can find them if you expand your search, and then simply toss away the unneeded functions.

If this is for building a handful or less, buy some cheap telephones and extract the IC (and keypad) from them.

As a side note, do they use the same tones over there as they do in North America? It's been a long time since I paid any attention to telephones, but it may be important to check.

Michael

DDS has always been the most popular method of generating DTMF, some modern designs use a micro with D/A, those true DTMF functions still manufactured are embedded in a larger chip containing everything from redial memory to speech circuits.

Thanks all, I have to reproduce an old ISA board for industrial control with a DTMF generator no more available. Probably the only repetible solution is to use a PIC, a ladder resistor network and some line of code, all the DTMF tone generator are obsolete and not recommended for new design (or for new redesign of old boards). Thanks again. Ciao. Bruno.

Usually is chiper to use a simple micro with a resistor network.

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Guess these chips become rare for the same reason floppy controller chips and UARTs slowly disappear: Their functions are embedded in larger chips or chipsets. It's not interesting for manufacturers to use DTMF-only chips. Another possibillity is to make DTMF by software. A small load for a fast 16 bits processor, negligible for a DSP. If you need a DTMF chip and can only find (too) expensive ones, you can make one your own by using a 8 bits micro. Atmel and Zilog, amongst others, have application notes about it. Google for "DTMF generation".

petrus bitbyter

TCM5089N:

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Service to my country? Been there, Done that, and I've got my DD214 to
prove it.
Member of DAV #85.

Michael A. Terrell
Central Florida

Or even just a PWM output going through a (reasonably stiff, actually, if you want low THD) low-pass filter.

Almost all the major microcontroller vendors have app notes out there not only on DTMF generation but also detection. The detection ones can be quite interesting -- it's there (for the TI MSP430 microcontrollers) I first heard about wave digitial filters, for instance.

Zarlink makes transceivers:

Marc