SV: [Sipforum-discussion] RE: [Sipping] Text support in SIP phones

[Gunnar Hellström <[e-mail]>]

OK, I think it would be fine to bring the introduction of real time text
conversation up for discussion in the SIPPING group.

I think that the small requirement statements we have discussed so far for
the sipdev specification are sufficient for that level.

But I have noticed some uncertainty from developers on what SDP to use to
open the RFC2793 text channel, and about some other good implementation
habits around the text channel. We need to be sure that there is good
agreement on such issues, so that we get maximum harmonization and
interoperability between implementations. ( real time text conversation in
the PSTN has a terrible history of fragmentation and incompatibility, and it
is time to make sure that is history now )

I want to have your advice if you want to see also SDP examples for the text
channel in the sipdev spec, in a separate Text Conversation Best Code of
Practice spec, or if there is any plan for a sipdev-technical guideline spec
where it could fit.


Gunnar

-------------------------------------------
Gunnar Hellström, Omnitor, Renathvägen 2
SE 121 37 Johanneshov, SWEDEN
Tel: [phone]  Mob: [phone]
e-mail: [e-mail]
web: www.omnitor.se


> -----Ursprungligt meddelande-----
> Från: Henry Sinnreich [mailto:[e-mail]]
> Skickat: den 11 juni 2003 11:59
> Till: 'Gunnar Hellström'; 'Sipping@Ietf. Org';
> 'Sipforum-Discussion@Lists. Su. Se'; 'Drage, Keith (Keith)'
> Ämne: RE: [Sipforum-discussion] RE: [Sipping] Text support in SIP phones
>
>
> Gunnar, thanks for bringing this up! I believe now we can ask for
> discussion time at the SIPPING WG meeting.
>
> Henry
>
> > -----Original Message-----
> > From: [e-mail]
> > [mailto:[e-mail]] On Behalf Of
> > Gunnar Hellström
> > Sent: Tuesday, June 10, 2003 2:42 PM
> > To: Henry Sinnreich; 'Drage, Keith (Keith)'; 'Sipping@Ietf.
> > Org'; 'Sipforum-Discussion@Lists. Su. Se'
> > Subject: SV: [Sipforum-discussion] RE: [Sipping] Text support
> > in SIP phones
> >
> >
> > I agree that this discussion starts to get balance into the
> > specification of the real time text conversation feature.
> >
> > Firstly, I have discovered that I need to explain again that
> > what we talk about is a real time, character by character
> > transmission and display of text. You can see the thought as
> > it is growing and being formed into text. It is a very direct
> > way to have contact, and once you have used it, you realize
> > that in some applications it is essential to have access to
> > this feature. It has the same immediate flow as audio in
> > voice telephony and video in video telephony.
> >
> > In fact, there is a name for the three media together, it is
> > called Total Conversation.
> >
> > It is true that the force behind defining it has come from
> > the needs of people with communication related disabilities.
> > But I am sure that once commonly implemented, it will become
> > a natural and popular feature that is often used during voice
> > calls between most users.
> >
> > Instant messaging is also a very handy service. But it goes
> > message by message, and therefore does not have the direct
> > touch as the real time conversational service in voice, text
> > and video has.
> >
> >
> >
> > We have a forerunner in the specification of media for the
> > SIP based IP Multimedia phone in 3GPP. Maybe we can pick the
> > same style of specification. In 3GPP TS 26.235, "Packet
> > switched conversational multimedia applications, default
> > codecs", it is specified among the enumeration of supported media:
> >
> > 6.3	Real time text
> > 3G PS multimedia terminals offering real time text
> > conversation should support ITU-T Recommendation T.140 [25]
> > Text Conversation presentation coding.
> >
> > And in the chapter on RTP payload, it is specified:
> >
> > 9.2	RTP payload
> > RTP payload formats specified by IETF shall be used for real
> > time media streams. RTP payload format for the AMR narrowband
> > speech codec is specified in annex B. RTP payload format for
> > the AMR wideband speech codec is specified in annex B. RTP
> > payload format for the ITU-T Recommendation H.263 [6] video
> > codec is specified in IETF RFC 2429 [3]. RTP payload format
> > for the MPEG-4 visual simple profile level 0 is specified in
> > IETF RFC 3016 [5]. RTP payload format for the ITU-T
> > Recommendation T.140 [25] text conversation coding is
> > specified in IETF RFC 2793 [24].
> >
> > In the annex A on specific details, the following is
> > specified for text:
> >
> > A.3	Text
> > Use of the redundancy coding variant specified in RFC 2793
> > [24] is recommended for error resilience.
> >
> > --------------------------------
> > When this topic was handled in 3GPP, there was opposition
> > against mentioning the reason for introducing the text
> > feature as being something specific for disabled people.
> >
> > I think that is still valid.
> >
> > I suggest that the following formulation is used:
> > **************************************************************
> > **************
> > **************************************
> > SIP-zz, digital text support: SIP telephone devices SHOULD
> > support real time text conversation. If text is supported, it
> > MUST support RFC2793 [y], for text coding and packetization,
> > and it MUST be possible to use text simultaneously with voice.
> > **************************************************************
> > **************
> > **************************************
> >
> >
> > Gunnar
> > -------------------------------------------
> > Gunnar Hellström, Omnitor, Renathvägen 2
> > SE 121 37 Johanneshov, SWEDEN
> > Tel: [phone]  Mob: [phone]
> > e-mail: [e-mail]
> > web: www.omnitor.se
> >
> >
> > > -----Ursprungligt meddelande-----
> > > Från: [e-mail]
> > > [mailto:[e-mail]]För Henry Sinnreich
> > > Skickat: den 10 juni 2003 18:02
> > > Till: 'Drage, Keith (Keith)'; 'Henry Sinnreich'; 'Gunnar
> > Hellström';
> > > 'Sipping@Ietf. Org'; 'Sipforum-Discussion@Lists. Su. Se'
> > > Ämne: [Sipforum-discussion] RE: [Sipping] Text support in SIP phones
> > >
> > >
> > > Keith, thanks for bringing balance, I believe, to this discussion.
> > >
> > > We could formulate soemthing like "SIP phones that have a
> > text display
> > > and advertised as supporting the hearing or speech disabled MUST..."
> > >
> > > Would this be OK?
> > >
> > > Henry
> > >
> > > > -----Original Message-----
> > > > From: [e-mail] [mailto:[e-mail]] On
> > > > Behalf Of Drage, Keith (Keith)
> > > > Sent: Tuesday, June 10, 2003 8:14 AM
> > > > To: 'Henry Sinnreich'; 'Gunnar Hellström'; 'Sipping@Ietf. Org';
> > > > 'Sipforum-Discussion@Lists. Su. Se'
> > > > Subject: RE: [Sipping] Text support in SIP phones
> > > >
> > > >
> > > > I would suggest that treating these sort of things as
> > MUST strength
> > > > is best left to national regulatory requirements, along
> > with other
> > > > things like fitness for purpose and so on. I have no objection to
> > > > their being mentioned. By the way, I understood this document was
> > > > being progressed as authors individual submission, and
> > was therefore
> > > > not standards track.
> > > >
> > > > Any such MUST would surely need to be qualified anyway. If the
> > > > purpose of the devise is such that it renders a textual devise
> > > > irrelevant, then why require one to be fitted. Suppose we were
> > > > designing a SIP phone for the totally blind, and this was
> > designed
> > > > to be worn as a headset, a text device would be
> > irrelevant to such a
> > > > user, and positioning such a device where it could be seen would
> > > > require an extra box hanging out of the side of the product.
> > > >
> > > > regards
> > > >
> > > > Keith
> > > >
> > > > Keith Drage
> > > > Lucent Technologies
> > > > Tel: [phone]
> > > > Email: [e-mail]
> > > >
> > > > > -----Original Message-----
> > > > > From: Henry Sinnreich [mailto:[e-mail]]
> > > > > Sent: 27 May 2003 17:18
> > > > > To: 'Gunnar Hellström'; 'Sipping@Ietf. Org';
> > > > > 'Sipforum-Discussion@Lists. Su. Se'
> > > > > Cc: 'Henry Sinnreich'
> > > > > Subject: RE: [Sipping] Text support in SIP phones
> > > > >
> > > > >
> > > > > Gunnar, this all seems very reasonable, and I will try
> > to insert
> > > > > it properly.
> > > > >
> > > > > Henry
> > > > >
> > > > > > -----Original Message-----
> > > > > > From: [e-mail]
> > [mailto:[e-mail]] On
> > > > > > Behalf Of Gunnar Hellström
> > > > > > Sent: Thursday, May 22, 2003 6:54 PM
> > > > > > To: 'Sipping@Ietf. Org'; Sipforum-Discussion@Lists. Su. Se
> > > > > > Cc: Henry Sinnreich
> > > > > > Subject: [Sipping] Text support in SIP phones
> > > > > >
> > > > > >
> > > > > > Sorry, I missed out the reference to the SIP device
> > > > > > specification.
> > > > > >
> > > > > > Henry and all,
> > > > > >
> > > > > > Some time ago, I suggested addition of support for real time
> > > > > > text communication to the SIP device specification
> > > > > >
> > > > >
> > > >
> > http://www.ietf.org/internet-drafts/draft-sinnreich-sipdev-req-00.tx
> > > > t
> > > > > >
> > > > > > This was the simple part of the proposal:
> > > > > >
> > > > > > > SIP-zz, digital text support: SIP telephone devices
> > MUST support
> > > > > > >   real time text conversation using RFC 2793 [y] for the
> > > > > > text stream.
> > > > > > >   It MUST be possible to use text simultaneously with voice.
> > > > > > >
> > > > > > >
> > > > > > >
> > > > > > > ---------------------------------------------
> > > > > > > In 4.11 Ringer Behaviour  : add the section below for the
> > > > > > purpose of
> > > > > > > deaf, hearing impaired, deaf-blind people and people in the
> > > > > > garden and
> > > > > > > noisy
> > > > > > > locations:
> > > > > > >
> > > > > > > SIP Telephony devices MUST provide an external
> > interface to an
> > > > > > > external alerting system.
> > > > > > >
> > > > > > >
> > > > > > >
> > > > > > > Add to References
> > > > > > > -----------------
> > > > > > > [y] G. Hellstrom: "RTP Payload for Text Conversation.",
> > > > RFC 2793,
> > > > > > > IETF, May 2000.
> > > > > > >
> > > > > > >
> > --------------------------------------------------------------
> > > > > >
> > > > > > The reception of this proposal was very positive.
> > > > > > Now, I would like to see the final formulation, and
> > check that
> > > > > > we agree on it.
> > > > > >
> > > > > > I regard this requirement to be very light. In the Interface
> > > > > > section ( e.g.
> > > > > > Int-2) , there is already mentioning of mandatory text input
> > > > > > mechanisms, and assumptions that a display would be normal,
> > > > > > since handling of phone books and buddy lists are
> > mandatory. To
> > > > > > re-use these text interface devices during the call for
> > > > > > standardised text conversation purposes seems straightforward.
> > > > > >
> > > > > > It could be wise to add the T.140 text presentation
> > protocol as
> > > > > > a codec to the codec section. The normal SDP used
> > together with
> > > > > > RFC2793 for text could also be specified. Do you want
> > > > > to do that?
> > > > > >
> > > > > >
> > > > > > -----
> > > > > >
> > > > > > We also need to check the ideas around the other proposed
> > > > > > requirements: The requirement to include text
> > telephone modem in
> > > > > > all designs where an RJ11 phone connector exists, and the
> > > > > > requirement to support RFC 3351. I suggest that we start with
> > > > > > the straightforward and mainstream requirement above. Is that
> > > > > > accepted as it is?
> > > > > >
> > > > > >
> > > > > > Regards
> > > > > >
> > > > > > Gunnar
> > > > > > -------------------------------------------
> > > > > > Gunnar Hellström, Omnitor, Renathvägen 2
> > > > > > SE 121 37 Johanneshov, SWEDEN
> > > > > > Tel: [phone]  Mob: [phone]
> > > > > > e-mail: [e-mail]
> > > > > > web: www.omnitor.se
> > > > > >
> > > > > >
> > > > > >
> > > > > > _______________________________________________
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> > > > > >
> > > > >
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> > > > >
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> > > > This list
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> > > >
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> > >
> > >
> >
> >
> >
>
>


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