Hi,

I have been developing a special tool for Skype-to-Skype calls that uses DTMF signals to control some external devices. It is extremely important for me that when I send the DTMF to called party, the beep is inaudible not only for the called party (as it is now), but also for the calling side (the one that "presses the dialpad"). I didn't find a way to do it. Am I wrong?

The answer "mute the wave input on your sound card" is not the right solution, I also need to transmit the audio from the called party back.

You may ask why I am not using the text messages - the problem is that I need the data transmitted absolutely synchronously and reliably with the phone call which is not the case of text messages -- my observation record was a message delivered almost 12 hours after it had been sent. But if DTMF isn't the right way, could you give me a hint for some other way to transmit data synchronously?

You might want to try implementing this logic in a Ap 2 Ap interface, and send your audio on a side connection, this would allow you to control, when it is heard, and when it is not.

Thanks for the advice, I am going to give it a try... although I got really pesimistic about this data transmission.

During my continuing tests I found out that DTMF is not even isochronous either! ...so I have to create some mix of sending instantly the control data supported by a continuous broadcasting of datagrams carrying the "timestamp" plus "current state" information... or do you have any better idea?