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Commanding a modem to send DTMF tones

Commanding a modem to send DTMF tones

Commanding a modem to send DTMF tones

Hi, I have a remote device that I can phone and control
via commands entered through the phone's keypad (DTMF
tones).  However, I am getting pretty tired of
punching the keypad to control the device and was
thinking of writing a small program that reads a text
file, converts the text to the equivalent phone key,
and sends it out via a modem.  To try it out, I used Win's Hyperterminal, sent out ATDT <tel #>, and was able to dial up to the remote device.  Here's the question: What modem (or AT) command do I use to send a DTMF tone (for example, I want to send 1 2 3 4 5 as DTMF tones)?  Everytime I type in a digit and hit enter the modem responds with NO CARRIER and drops the connection.
Thanks.  Joe

RE: Commanding a modem to send DTMF tones

Please, I need some help.
What can I do to send a DTMF tone of 1400hz and 2300hz from my modem to another modem?  

RE: Commanding a modem to send DTMF tones

I want to know how can i recognized a DTMF tone , once the comunication has established between a phone and a modem.
thank you

RE: Commanding a modem to send DTMF tones

Lourdes tu lo que quieres es un handshake  a 1400 o 2300 Hz para dar un saludo a un sistema muy especializado, como por ejemplo el panel de una alarma, y si lo estás intentando con un modem convencional, siento decirte que x hay no van los tiros, ya que un modem se comunica con otro con las normativas correspondientes, donde unos de los parametros que tienen estas normas p.e. V.29 o la V.34, son el tono inicial que tienen que generar, es decir a que frecuencia tiene que oscilar el cristal interno para generar ("el chillido") del modem que escuchas cuando se conecta con otro modem, de todas, manera te dire que si encuentras una solucion al temna, estaría muy interesado, ya que yo tambien estoy trabajando en ese camino. Mi direccion es luli01@teleline.es

Recibe un saludo,   Angel.

RE: Commanding a modem to send DTMF tones

To send DTMF tones after you have dialed a remote computer you must type ATDT<#>, just like when you are dialing a number.  If you are already connected to the remote computer you must type +++ATDT<#> to put your modem in command mode.  To return to online mode just type ATO.  The +++ are escape characters which put your modem in command mode.  If you want your modem to send data then you must return to on-line mode, using the ATO command.

RE: Commanding a modem to send DTMF tones

Hi du1lbx, i have read your message and i think i need your help. How can i use the phone and control via commands entered through the phone's keypad (DTMF tones). please help me. Thanks.

RE: Commanding a modem to send DTMF tones

Hi I've successfully connected using GSM Modem to voice call
but i'm kinda stucked when I wanted to issue DTMF tone

Basically what i need to do:
1. dial 97600000
2. select 1
3. key in 7782251603528033 followed by # key

what I've done:

this step was supposed to top-up my SIM Card Value
but it dont work that way
Did i miss anything?


RE: Commanding a modem to send DTMF tones

try using the command +vts to send DTMF signal, but the prob with this is it only takes in 0-9,#,*,A,B,C,D, so for a long sequence of numbers, eg 2093845, you will need to type in either of these two ways:




RE: Commanding a modem to send DTMF tones

hello! i've been getting error messages when i use the +vts command to send dtmf signal using a long sequence of numbers since last week. i tried kuuga's solution, the carrier-return <CR> separated series of commands and it worked! thanks kuuga! Ü

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