You can't. I've seen some systems implement a hint in Alert-Info, but it is not standardized. There is some text in 3PCC about using local URI conventions.
Generally, you can't use a protocol like SIP to force the other end to do something, because it's a security risk. Alert-Info has a note about that. Brian > -----Original Message----- > From: [EMAIL PROTECTED] [mailto:sip-implementors- > [EMAIL PROTECTED] On Behalf Of ??? > Sent: Tuesday, October 19, 2004 7:31 AM > To: Brian Rosen; [EMAIL PROTECTED] > Subject: [Sip-implementors] Re: [SIPPING] automatic answer > > Thanks Brian, > > What I am telling is to force the phone to answer (to send 200 OK without > user intervention) by which params in INVITE. > > That functionality is required to send/receive some information on the > phone to/from the server. > > > BR > > Jinkyung Hwang > KT > > ----- Original Message ----- > From: "Brian Rosen" <[EMAIL PROTECTED]> > To: "'황진경'" <[EMAIL PROTECTED]>; <[EMAIL PROTECTED]> > Sent: Tuesday, October 19, 2004 8:12 PM > Subject: RE: [SIPPING] automatic answer > > > Redirected to sip-implementors > > As with any automatic answering system, you don’t need any standards. You > just answer (send 200 OK). > > You can’t force (or signal) the called party to answer; it makes its own > decision. > > The UAC sends INVITE > The UAS could send a 180 if it wants; sometimes it’s disconcerting to get > the answer too quickly > The UAS sends 200 OK > > That’s it. > > Brian > > ________________________________________ > From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf > Of ??? > Sent: Tuesday, October 19, 2004 1:17 AM > To: [EMAIL PROTECTED] > Subject: Re: [SIPPING] automatic answer > > Dear Folks, > > > I have not found out the related I-D or RFC regarding "automatic answer > feature" for SIP phone. > > To implement in the SIP phone, is it reasonable to use Call-Info field ? > > > Any reponse would be appreciated. > > > Jinkyung Hwang > KT > > ----- Original Message ----- > From: 황진경 > To: [EMAIL PROTECTED] > Sent: Saturday, October 09, 2004 12:01 PM > Subject: automatic answer > > Hi, > > Is there any I-D regarding params for SIP phone to answer automatically ? > (for answering machine functionality) > > I would like to know when the call arrives a phone, by which param/header > value the phone answers without ringing. > > > > Any reponse would be appreciated. > > > Jinkyung Hwang > KT > > > _______________________________________________ > Sip-implementors mailing list > [EMAIL PROTECTED] > http://lists.cs.columbia.edu/mailman/listinfo/sip-implementors > _______________________________________________ Sip-implementors mailing list [EMAIL PROTECTED] http://lists.cs.columbia.edu/mailman/listinfo/sip-implementors
