[Asterisk-Dev] Distinctive ringing

John Todd jtodd at loligo.com
Fri Jun 20 12:20:52 MST 2003

>On Fri, 2003-06-20 at 11:15, Jayson Vantuyl wrote:
>>  On Tue, Jun 17, 2003 at 12:03:49PM -0700, John Todd wrote:
>>  > There is a pending patch that Mark has been given (by "km-", whose
>>  > real name I don't recall) that will add this "distinctive ring"
>>  > feature to Asterisk, by setting a variable before sending a call to a
>>  > SIP outbound channel via Dial.
>>  Is there a similar way to signal a distinictive ring with Zaptel?
>I've off and on thought about this, and the comments about how no known
>phone right now is RFC compliant. The comments have said that there are
>a couple of different ways of signaling the different rings.
>This brings me to the idea that could potentially bring the dial command
>back to something usable just like the zapata way. Could you not make
>ring definitions on a per sip user basis and reference them with a
>number just like the way we do with zapata? Maybe in a homogeneous SIP
>device environment you could define the distinctive rings in the general
>section, but in a heterogeneous environment the ability to set the rings
>local to the user/phone would eliminate the problem of the RFC says to
>provide a URL, but cisco says an integer is enough.
>I'll admit I don't have enough knowledge of how SIP works to do any more
>than suggest this to those who may make the changes.
>Steven Critchfield  <critch at basesys.com>

[prior responses to this have already addressed the basic question of 
how to get Zaptel devices to use distinctive ringing]

Steve -
   Using a numeric is still not compliant to the spirit of the 
Alert-Info: header information.  The problem is that SIP phones may 
not be sitting on your LAN, using your ringers, or even owned by you, 
and it's more likely that remote SIP phones aren't even "known" by 
Asterisk until the moment they are dialed - this rules out a prior 
mapping of a numeric to a particular ringtype.  Including a 
fully-qualified URL in the Alert-Info: header is the only way to 
ensure that the soundfile that you specify will be possibly be 
accessed by the remote phone.

   Of course, there is no "MUST" in the usage for Alert-Info: so it 
starts to become dependent on each vendor as to how they implement 
distinctive ringing.  Using a numeric might suffice and be compatible 
with the Zap channel syntax, but I would suspect that this will not 
be a viable solution when vendors start to implement the ringtypes.

Side note: Remember when all cellphones had one ringer?  As the 
technology of cellphone call delivery became "commonplace", the focus 
of vendors moved away from basic functionality into the shiny, stupid 
features like playing "1812 Overture" with the ring alert.  SIP isn't 
to the point where the basic functionality is completely nailed down, 
but within the next year expect to see the "bells and whistles" 
features start to become more developed as vendors shift their dev 
teams away from core functionality (which will be completed.) 
Putting the feature hooks in correctly _now_ will save a lot of 
headache if we can guide the vendors into building features to match 
the hooks in a scaleable way.


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