Subject: RE: [Megaco] Comfort Tone?

From: "Blatherwick, Peter" <[email-masked]>
Date: Tue, 20 Nov 2001 20:30:34 -0500

MY comfort tone is really really loud clashing guitars...   Oh, sorry, you were probably looking for a standards kind of definition.  (Sorry, could not resist.  ;-)   

Seriously, what "comfort tone" do you mean?  Do you mean the noise intentionally put in by codecs to mask the uncomfortable sound of real silence, do you mean those little tones on hold to tell you the call is still alive?  What specific reference are you trying to resolve?  

-- Peter

-----Original Message-----
From: Paul Long [mailto:[email-masked]]
Sent: November 20, 2001 19:27
To: [email-masked]
Subject: [Megaco] Comfort Tone?

Anyone know what the aural characteristics of comfort tone are? IOW, what
the heck does it sound like? I know this could vary from region to region,
but I can't recall ever hearing it or seeing a description of it.

Paul Long
ipDialog, Inc.

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From: "Kevin Boyle" <[email-masked]>
Date: Thu, 22 Nov 2001 11:51:13 -0500

Comfort tone is the white noise generated to keep people from thinking their
phone line is dead.  People seem to get very uneasy when met with the
absolute silence of the digital world, and much prefer the fuzzy silence of
the analog world.

The "little tones" that indicate that you are on hold are known as "held
tone".  While they may provide you comfort, they are not "comfort tone".

Kevin

 -----Original Message-----
From: 	Blatherwick, Peter [mailto:[email-masked]] 
Sent:	Tuesday, November 20, 2001 8:31 PM
To:	'Paul Long'; [email-masked]
Subject:	RE: [Megaco] Comfort Tone?

MY comfort tone is really really loud clashing guitars...   Oh, sorry, you
were probably looking for a standards kind of definition.  (Sorry, could not
resist.  ;-)   

Seriously, what "comfort tone" do you mean?  Do you mean the noise
intentionally put in by codecs to mask the uncomfortable sound of real
silence, do you mean those little tones on hold to tell you the call is
still alive?  What specific reference are you trying to resolve?  

-- Peter

-----Original Message-----
From: Paul Long [mailto:[email-masked]]
Sent: November 20, 2001 19:27
To: [email-masked]
Subject: [Megaco] Comfort Tone?

Paul Long
ipDialog, Inc.

---

From: "Kevin Boyle" <[email-masked]>
Date: Thu, 22 Nov 2001 12:15:04 -0500

I believe you are referring to E.182.  E.180 most certainly is a definitive
standard, defining frequency and cadence ranges that are permitted by
international standard.  E.182 lists the nationalized tonesets, which may or
may not be compliant to the E.180 standard.

Kevin

 -----Original Message-----
From: 	Vance Shipley [mailto:[email-masked]] 
Sent:	Wednesday, November 21, 2001 1:22 PM
To:	Paul Long
Cc:	Megaco
Subject:	RE: [Megaco] Comfort Tone?

Paul Long writes:
> It says that comfort tone varies from system to system, although they 
> use a continuous 480Hz tone (I wonder what waveform, though). So there 
> may not be a standard for this tone, unlike dialtone and busy.

As someone who spends a lot of time referencing E.180 "Various Tones used
in National Networks" I would dispute the statement that there was a
standard for dialtone and busy.  We make call progress analysis software
for answer supervision detection.  We find some pretty bizarre tones used
in national networks.

E.180 is an annex to the operational bulletin and is really just a 
collection of statements provided by national operators.  It isn't by
any means definitive, or even remotely accurate, unfortunately.

	-Vance

Vance Shipley
Motivity Telecom Inc.
+1 519 579 5816