Hi, last week I saw a cool feature in a PBX that seems me very useful
for hotel PBX's and so.
I typed 143 in my room phone to call a friend in that room. My
friend's name is... Bob? XD
When the call progress started I saw in my phone led "Calling Bob...".
Well, the only way we can do that in SIP is by giving the phone the
ability of search into a contacts addressbook for the typed number and
retrieve the extra info (as DisplayName) using any other protocol
(http, ldap...). This way is not very nice (always) since the phone
needs inteligence to access to the addressbook resource using other
non SIP protocol (and note each phone model implements different ways
to access a remote addressbook, some of them using vendor private
protocols or formats).
Sometimes the only real need is just to verify that the number dialed
retrieves the Display Name expected (imagine a phone in a hotel room
that doesn't need to offer the user an addressbook and so).
So I wonder if there is a mechanism in SIP that allows the calling
party retrieve the callee Display Name (an maybe more info) during the
call.
I see that "Call-Info" in the response can be used to achieve this but
it doesn't provide a *fast/easy* way:
20.9 Call-Info
The Call-Info header field provides additional information about the
caller or callee, depending on whether it is found in a request or
response. The purpose of the URI is described by the "purpose"
parameter. The "icon" parameter designates an image suitable as an
iconic representation of the caller or callee. The "info" parameter
describes the caller or callee in general, for example, through a web
page. The "card" parameter provides a business card, for example, in
vCard [36] or LDIF [37] formats.
Call-Info = "Call-Info" HCOLON info *(COMMA info)
info = LAQUOT absoluteURI RAQUOT *( SEMI info-param)
info-param = ( "purpose" EQUAL ( "icon" / "info"
/ "card" / token ) ) / generic-param
I don't like this since the calling phone needs to be able to use
other protocols (and read formats like vCard or LDIF). This is not
cool and involves risks.
I've an idea for that by using a new header "Callee-Info":
phone A (140) phone B (143)
--------- INVITE (1) ------>
<------- 180 Ringing (2) ------
(1)
INVITE sip:[EMAIL PROTECTED] SIP/2.0
From: <sip:[EMAIL PROTECTED]>
To: <sip:[EMAIL PROTECTED]>
(2)
SIP/2.0 180 Ringing
From: <sip:[EMAIL PROTECTED]>
To: <sip:[EMAIL PROTECTED]>
Callee-Info: display_name="Bob";other_info="xxxxx"
So phone A could render "Bob" as the dialed user in the screen.
I'd like something as simple as this could be possible using
"Call-Info" header but it's not since it requieres the use of an
absolute URI.
Any other suggestion? Thanks.
--
Iñaki Baz Castillo
<[EMAIL PROTECTED]>
--
Iñaki Baz Castillo
<[EMAIL PROTECTED]>
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