[Asterisk-Users] InfoWeek Article on VOIP

[trixter http://www.0xdecafbad.com]

On Sat, 2005-07-16 at 16:12 -0700, Bruce Ferrell wrote:
> It's sometimes called comfort noise... As far as I'm aware, it's only 
> done in VoIP.
>
> I spent 15 years working with digital switches/T1 channel banks.  I 
> guess it might have been built in and I just didn't know about it, but 
> we were very concerned about excess noise and quantization noise as it 
> was.  We used to inject a 1004 test tone and then use a notch filter to 
> measure the amount of quantization noise at the reciever.
> 

I have seen it done at the switches that telcos use, not at the end user
such as in a channel bank.  

-- 
Trixter http://www.0xdecafbad.com     Bret McDanel
UK +44 870 340 4605   Germany +49 801 777 555 3402
US +1 360 207 0479 or +1 516 687 5200
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