SLUG Mailing List Archives
Re: [SLUG] Best Linux soft-phone?
- To: Simon Wong <linux@xxxxxxxxx>
- Subject: Re: [SLUG] Best Linux soft-phone?
- From: Glen Turner <glen.turner@xxxxxxxxxxxxx>
- Date: Fri, 25 Aug 2006 16:28:49 +0930
- Cc: slug@xxxxxxxxxxx
- Organization: Australia's Academic & Research Network
- User-agent: Thunderbird 188.8.131.52 (X11/20060808)
Simon Wong wrote:
I use this regularly now as the call quality is significantly *better*
than a std Telstra phone line as it has the G711U codec.
Your analogue home phone actually runs G.711 A-law. The codec
is in the PABX in the exchange -- it outputs 8-bit A-law samples
into the time-division multiplexed backplane of the PABX which
is then carried across SDH bearers to another PABX where is
is demultiplexed and decodeced onto the analogue line to the
So if VoIP running G.711 μ-law has a perceptual advantage then
you'll need to look further than the codecs involved.
A-law sampling is basically the same a μ-law sampling, except
that the curve on the A-law gives it a greater dynamic range
(μ-law was a bit too conservative about the performance of the
last mile copper).