AVD-2244 H.248 Implementors Guide Draft

Terry L Anderson tlatla at VERIZON.NET
Sat Jun 22 00:35:06 EDT 2002

Poul and all,

This is my view:

T.140 is the presentation protocol for text conversation, now acknowledged
to be the standardised medium for text during a real time multimedia session
in all standardised multimedia protocols: H.320, H.324, H.323, 3G.324, SIP,
and also in V.18 text telephony, T.120 data conferencing and 3GPP mobile
text telephony.

It is intended to be the third default medium taking video telephony into
Total Conversation.
It gives extra value to any videophone implementation. I work daily with it
and often experience the power of the three media of video, text and voice

The media flow is character by character, so it gives a live view of the
text conversation as the thoughts are formed into typed words, just as the
other real time media carries the thoughts as they are formed into spoken
words in the audio channel or visual expressions in the video channel.

It is Unicode based and specifies a very limited set of editing controls
suitable in a real time text conversation.

It also forms a migration path for text telephone users into new network
environments and higher functionality communication services.

For each multimedia protocol, there is a specification about how a T.140
media stream is opened and transported according to the habits in that
protocol environment.

All call handling aspects are handled by the multimedia protocol

Services including T.140 text conversation are defined in F.703 Multimedia
Conversation Service description.

Instant Messaging
Instant messaging is more of a complete service in its own right, including
addressing, notification, alerting, transmission etc. It is usually regarded
to be not really real time conversational. Instead it offers the opportunity
to formulate a message first and then transmit the whole message. Some
instant message services can enter a real time character by character mode.
In that mode, the user experience of the text part is usually very similar
to using T.140.

Both have very good reasons to exist. Sometimes a real time conversation is
most effective for the purpose of developing thoughts and agreements
together, sometimes an instant message exchange is more appropriate since it
does not require the same real time devotion from the users.

Maybe someone can brief us on the standardisation situation for Instant


Gunnar Hellström
Gunnar Hellström
Omnitor AB
Renathvägen 2
SE 121 37 Johanneshov
+46 8 556 002 03
Mob: +46 708 204 288
Gunnar.Hellstrom at Omnitor.se
  -----Ursprungligt meddelande-----
  Från: Mailing list for parties associated with ITU-T Study Group 16
[mailto:ITU-SG16 at echo.jf.INTEL.COM]För Paul Long
  Skickat: den 21 juni 2002 21:29
  Till: ITU-SG16 at echo.jf.INTEL.COM
  Ämne: IM and T.140

  What's the difference between "instant messaging" in general and T.140?
IOW, what can you do with one that you can't do with the other?

  Paul Long
  ipDialog, Inc.
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