dtmf =freq+freq

[erik]

Hi,

Who can tell me the frequenties of the dtmf's?
'1' = ....... Hz + ...... Hz
'2' = etc.

quenstion 2. Can anyone send me the tones in a wav-file (or other
file-formate) ?

Thanks in advance,

Erik

Eri...@unit4.nl

[Robert Clark]

A quick search via Alta Vista on 'DTMF' led to

http://home.wxs.nl/~napel/dial.htm

where I think you will find what you want.

Good luck
And try Alta Vista next time ( :))>

Bye
RC

erik <eri...@unit4.nl> wrote in article
<68vtej$cft$1...@news.worldonline.nl>...

[Roderick Buck]

In article <68vtej$cft$1...@news.worldonline.nl>, erik <eri...@unit4.nl>
writes

>Hi,
>
>Who can tell me the frequenties of the dtmf's?
>'1' = ....... Hz + ...... Hz
>'2' = etc.
>
>quenstion 2. Can anyone send me the tones in a wav-file (or other
>file-formate) ?
>
>Thanks in advance,
>
>Erik
>
>Eri...@unit4.nl
>
>
>

There are 2 implementatations in use:

Imagine the phone keypad like so, but with a 4th row to the right:

1209hz 1336hz 1477hz 1633hz
====== ====== ====== ======

697hz 1 2 3 A

770hz 4 5 6 B

852hz 7 8 9 C

941hz * 0 # D

This is the normal implementation, for telcom use.

dtmf chips for keypad use have 8 input lines, corresponding to the rows
and columns above.

grounding 1 row + 1 col input (or sometimes connecting them together)
generates the appropriate tones for the digit.

E.g grounding row 4 + col 3 = #

row 2 + col 2 = 5

However some DTMF chips use binary adressing, so that that the chip is
addressed by 4 binary lines (1 nibble).

In this case, the coding may be either:

Digit Binary Decimal
===== ====== =======
1......0001......1
2......0010......2
3......0011......3
4......0100......4
5......0101......5
6......0110......6
7......0111......7
8......1000......8
9......1001......9
0......1010......10
*......1011......11
#......1100......12
A......1101......13
B......1110......14
C......1111......15
D......0000......0

(remember, the "0" button on a phone is really "10", as in pulse-dial
phones, where instead of 0 pulses, it gives 10.)

or, the chip can give:

D Binary Decimal

0......0000.......0
1......0001.......1
2......0010.......2
3......0011.......3
4......0100.......4
5......0101.......5
6......0110.......6
7......0111.......7
8......1000.......8
9......1001.......9
*......1010.......10
#......1011.......11
A......1100.......12
B......1101.......13
C......1110.......14
D......1111.......15

- a true binary generation.

The first one is now more common, but some chips, like Plessey 8870 can
be switched from one to another by having a pin high or low.

Hope this doesn't confuse!

rodbuck@ telespeed.demon.co.uk

--
Roderick Buck

[Peter Hazenberg]

erik wrote:

> Hi,
>
> Who can tell me the frequenties of the dtmf's?
> '1' = ....... Hz + ...... Hz
> '2' = etc.
>
> quenstion 2. Can anyone send me the tones in a wav-file
> (or other
> file-formate) ?
>
> Thanks in advance,
>
> Erik
>
> Eri...@unit4.nl

Beste Erik,

Hier de "dual tone (multi) frequenties" van je telefoon; (in
Hz)

1= 697+1209 4= 770+1209 7= 852+1209 *=941+1209
2= 697+1336 5= 770+1336 8= 852+1336 0=941+1336
3= 697+1477 6= 770+1477 9= 852+1477 #=941+1477
A= 697+1633 B= 770+1633 C= 852+1633 D=941+1633

In Nederland (lees Europa) worden de letter A t/m D niet
uitgevoerd op je telefoon. Dit is wel het geval in USA.

Om de tone op te slaan in je computer kun je met een
microfoon voor je hoorn al heel behoorlijke opname maken.
Een lijnaftak (bv. via twee 100n C'tjes) aan je 'line-in'
geeft uiteraard een beter resultaat. (Pas op voor
wekspanningen als iemand je probeert te bellen)

Over een beetje ruis hoef je je niet al te veel zorgen te
maken, want het protocol rondom 'DTMF' is uiterst robuust en
DTMF apparatuur kan daar prima mee overweg.

Voor meer informatie over telecom weet je me nu te vinden.

Veel succes ermee.

Vriendelijke groet,

Peter Hazenberg