H.323 Annex F - SET questions

Gunnar Hellstrom gunnar.hellstrom at OMNITOR.SE
Sun Apr 18 17:05:18 EDT 1999

Dear Jörg and all,
When preparing H.323 Annex G - Text SET, I studied the base SET document;
Annex F as in TD11 from Monterey, and came across a few points raising

I hope I can get clarifications on these points.

1. In section 6. it is said that for the Audio SET, "Data-capability is
optional - possibly support for facsimile transmission." If this section is
as is stated - for the Audio SET, then "No Data Capability" should be
And I think that is a good structure - Then I can write that the Text SET
has Media Capabilities as for the Audio Set but with Data Capability for
text conversation according to T.140.

2. In section 7.3.2. the explanations of the abbreviations M O I N, refers
to Audio SET devices. The rest of this section looks general, why I suggest
that the word "Audio" should be deleted in these four explanations.

3. Media Exchange. Insert TCP among the allowed protocols, so that data
transmission SET:s can be allowed.

4. In section 7.6.1, the last sentence is "The OpenLogicalChannel structure
should offer the same audio encodings that were in use prior to call
rerouting." Looking back to the discussions in the list the last few weeks,
I find that this sentence is misleading and can safely be deleted. The
result should be that coding changes and media additions shall be allowed
to occur after the rerouting.

5. In section 7.6.2, change the word "resume" to "start" in the last
sentence. Since media additions may occur, media streams may be new after
the rerouting.

6. Terminal type for SET types.
I want to discuss the "Endpoint Type" specification in H.225.0 as described
among the additions to implementor´s guides, titled "Addition of a terminal
type for Simple Endpoint Types"and in Annex F, section 7.1.
Bit 0 =1  if the device is an Audio SET.
My question is: Should this specifier rather mark available functions than
complete SETs?
Then, bit 0 could indicate "the device has Audio functions"
and , bit 2 could indicate "the device has Text conversation features."
A Text SET should set them booth.
This would allow for a combined text - fax - audio -SET.


Gunnar Hellström

Gunnar Hellström
Omnitor AB
Alsnögatan 7, 4tr
S-116 41 Stockholm

Tel +46 751 100 501
Fax +46 8 556 002 06

E-mail: gunnar.hellstrom at omnitor.se
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