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DTMF generator

B

Bru

Jan 1, 1970
0
I'm looking for a DTMF generator chip, it seams that this kind of chip is no
more available.
Any help will be very appreciated.
Ciao.
Bruno.
 
M

Michael A. Terrell

Jan 1, 1970
0
Bru said:
I'm looking for a DTMF generator chip, it seams that this kind of chip is no
more available.
Any help will be very appreciated.
Ciao.
Bruno.


http://www.clare.com/products/dtmf.htm 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.


--
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
 
H

Hal Murray

Jan 1, 1970
0
I'm looking for a DTMF generator chip, it seams that this kind of chip is no
more available.
Any help will be very appreciated.

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

Michael Black

Jan 1, 1970
0
Bru" ([email protected]) said:
I'm looking for a DTMF generator chip, it seams that this kind of chip is no
more available.
Any help will be very appreciated.
Ciao.
Bruno.
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
 
I

ian field

Jan 1, 1970
0
Hal Murray said:
What do people use these days? Maybe a micro with a D/A?


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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.
 
B

Bru

Jan 1, 1970
0
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.
 
B

Bru

Jan 1, 1970
0
Usually is chiper to use a simple micro with a resistor network.
 
P

petrus bitbyter

Jan 1, 1970
0
Bru said:
I'm looking for a DTMF generator chip, it seams that this kind of chip is
no
more available.
Any help will be very appreciated.
Ciao.
Bruno.

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
 
M

Michael A. Terrell

Jan 1, 1970
0
Bru said:
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.

TCM5089N:

<http://home.earthlink.net/~mike.terrell/Epsem.html>
<http://www.jameco.com/webapp/wcs/st...storeId=10001&catalogId=10001&productId=32803>
--
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
 
J

Joel Kolstad

Jan 1, 1970
0
Hal Murray said:
What do people use these days? Maybe a micro with a D/A?

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.
 
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