[asterisk-users] Are the Siren7 and Siren14 the G.722 HD voice codecs?

[Kevin P. Fleming]

On 01/05/2011 01:29 AM, Bruce B wrote:
> Hi Everyone,

You should really spend some time learning how to use a widely available 
search engine, such as Google or Bing. Many of the questions you ask 
here could be quickly answered that way.

>
> 1- Are the Siren7 and Siren14 the G.722 HD voice codecs?

That depends on what you mean by "the G.722 HD voice codecs". G.722 (no 
suffix or annex) is a specific voice codec, and it is unrelated to 
Siren7 and Siren14. G.722.1 is the same thing as Siren7, and G.722.1 
Annex C is the same thing as Siren14. These are fairly well explained on 
the Wikipedia pages for G.722 and G.722.1.

> 2- Are these codecs only for Polycom units or are they universal across
> all other SIP phones that advertise the HD voice codec like Aastra?

There is no "the HD voice codec". The most widely available HD voice 
codec is G.722, but there are others available as well in endpoints from 
various manufacturers. G.722.1 and G.722.1C are available in many 
Polycom SIP devices, but not yet widely available in other devices 
(although there are softphones that have them), although they are 
available as binary add-on modules for Asterisk.

> 3- What is the main difference between the two and is it advisable to
> run these over the INTERnet (not INTRAnet)?

Which "two" are you referring to here?

G.722 is frequently used over the Internet (the weekly VUC makes it 
available, for example), and G.722.1/C use less network bandwidth than 
it does, so they should be usable in the same situations as well. 
Whether they are advisable for you to use or not depends entirely on 
your network connectivity, bandwidth and packet loss situation. None of 
them use more network bandwidth than G.711, though, so if your network 
connections can already handle G.711 calls without causing unacceptable 
audio disturbance, you should be fine using any of these codecs as well.

-- 
Kevin P. Fleming
Digium, Inc. | Director of Software Technologies
445 Jan Davis Drive NW - Huntsville, AL 35806 - USA
skype: kpfleming | jabber: kfleming at digium.com
Check us out at www.digium.com & www.asterisk.org