[Asterisk-Users] Why echo occurs

[Steven Critchfield]

On Fri, 2005-02-11 at 15:05 +0800, Steve Underwood wrote:
> Steven Critchfield wrote:
> 
> >On Fri, 2005-02-11 at 15:35 +1100, Eric Bishop wrote:
> >  
> >
> >>2. Is only a problem in 2-wire technologies (ie analog and BRI ISDN lines)?
> >>    
> >>
> >
> >It is just an analog problem. That is why a BRI can actually transmit
> >direct digital data instead of audio data. 
> >  
> >
> There is enough spill from the earpiece to the mike on most phones, that 
> EC is required even on a digital phone.

Fine, but to get an earpiece, you make an analog portion of the link
unless someone has made some digital ears with direct data jacks on the
side of human heads.

So if you say that a SIP handset is like a 4 wire set, and BRI is like a
4 wire set, and asterisk doesn't mix the ins and outs, you effectively
are 4 wire through the portion you can control. The remote side is up to
whoever you call. 
-- 
Steven Critchfield <critch at basesys.com>