[Freeswitch-users] Stupid question of the week: how to generate silence and still detect DTMF

[Andy Spitzer]

Woof!

On Wed, 09 Jul 2008 12:49:51 -0400, Anthony Minessale <anthony.minessale at gmail.com> wrote:

> you can try 1,1 instead of 0,0 which is still silent

Actually, it isn't.  It is quite audible on several phones I've played with (most likely due to the uLaw companding adding a "step" to each voltage, and poor analog filters on the phones), and it also has an RMS power value that is certainly not low energy.

I've tried lots of variations of power and frequency and have found nothing as truly silent as 0,8000 (or 0,16000 and 0,32000)  I'm just worried that if we ever see a codec that isn't a multiple of 8Khz, it wouldn't be silence anymore.


--Woof!