Subject: Re: [Sipping] New Tones draft (was: "who plays the tone" or something like th...

From: [email-masked]
Date: Mon, 23 Jun 2003 13:25:09 EDT

In a message dated 6/23/2003 2:02:12 AM Eastern Standard Time, 
[email-masked] writes:

>  wrote the following draft in order to provide some discussion on 
> alternatives to in-band early-media ringback, and to discuss the issue 
> of playing tones in general which I believe is inherently linked to 
> 3pcc and application interaction.
> 

Rohan,

This seems to handle the general case of instructing a UA to generate a tone 
based on a specific set of characteristics (frequencies, levels, duration, 
decay, modulation, etc.) One of the immediate questions is what is the full set 
of possibilites required and what happens when someone wants a tone that is 
outside of that defined set? For example, you've shown examples of "decay", but 
what if the required tone starts low and gets louder? Luckily, no one has used 
a tone that varies in frequency over time.

I didn't see anything in your write-up or in RFC 2833 about specifying which 
direction the UA should send the tone. There can be cases which the UA needs 
to be told:

1. send the tone only to the user of that UA (e.g., Call Waiting)
2. send the tone only to the other end (e.g., Audible Ringing)
3. send the tone to both (e.g., Recorder Warning)

Volume is defined with a range of -3 to -63 decibels. However, I believe that 
off-hook warning tone needs to be higher than -3 dB. Or maybe this function 
should be done in a different way, since the UA is presumed to have other 
alerting mechanisms (like ringing when already "off-hook").

This proposal would work, if every UA were required to support it.

Mike Pierce