Subject: RE: [Megaco] Fax and Modem detection

From: "Kevin Boyle" <[email-masked]>
Date: Mon, 16 Jan 2006 17:51:31 -0500

If the MGC requests it, yes.

Kevin 

-----Original Message-----
From: Wainwright, John (Com US) [mailto:[email-masked]] 
Sent: Monday, January 16, 2006 5:32 PM
To: Boyle, Kevin [NCRTP:3Z40:EXCH]; [email-masked]; Gunnar
Hellstrom
Cc: [email-masked]
Subject: RE: [Megaco] Fax and Modem detection

If the MG behavior is autonomous with regards to VAD/Echo cancellation
when it detects CNG does it still report the ObservedEvent ctyp/dtone to
the MGC ?

John

-----Original Message-----
From: Kevin Boyle [mailto:[email-masked]]
Sent: Monday, January 16, 2006 12:58 PM
To: Wainwright, John (Com US); [email-masked]; Gunnar
Hellstrom
Cc: [email-masked]
Subject: RE: [Megaco] Fax and Modem detection

The packages in H.248.2 got reworked some time ago to allow the MG to
perform autonomous switchover.  This solves race condition issues
between the timing requirements of the fax protocols and H.248 message
RTTs.  Generally speaking, autonomous behavior for switchover to fax is
better.  But it would all depend upon the SDP setup and the indications
in the package when the MGC adds the events to the Events Descriptor.

For VBD, recall that if the proper setup is achieved in the SDP
exchange, the MG must be ready to accept packets of any kind at any
time.  This, essentially, mandates autonomous switchover if the VBD is
an alternative in the SDP and the MGC has specified the RG and RV
properties as true.

Kevin

-----Original Message-----
From: [email-masked] [mailto:[email-masked]] On Behalf
Of Wainwright, John (Com US)
Sent: Monday, January 16, 2006 11:21 AM
To: [email-masked]; Gunnar Hellstrom
Cc: [email-masked]
Subject: RE: [Megaco] Fax and Modem detection

Also, just to clarify for myself, after detection and reporting of the
CNG tones via the  ctyp/dtone observed event should the MG automatically
turn off Voice Activity Detection (VAD) and Echo Cancellation - again
the assumption is that G.711 us being used - or should it wait for the
MGC to tell it to do this ?

Thanks
John

-----Original Message-----
From: [email-masked] [mailto:[email-masked]]
Sent: Saturday, January 14, 2006 8:53 AM
To: Wainwright, John (Com US); Gunnar Hellstrom
Cc: [email-masked]
Subject: RE: [Megaco] Fax and Modem detection

John,
like to complement Gunnar.

You are looking for VBD mode (VBDoIP; e.g., according ITU-T V.152).
There is NO H.248 Package required for the CONTROL of VBD (see also
V.152), but if you want to NOTIFY the MGC about the detection of a VBD
stimuli then you may use H.248.2 ctyp.
The Event ctyp/dtone is typically sufficient ("the observed event
parameter dtt may be used in addition for discriminating tone types, but
I never saw so far this requirement and application in the context of
VBDoIP").

- Albrecht

                      "Gunnar Hellstrom"

                      <gunnar.hellstrom@         To:      "Wainwright,
John \(Com US\)" <[email-masked]>,                  
                      omnitor.se>                <[email-masked]>

                      Sent by:                   cc:

                      megaco-bounces@iet         Subject: RE: [Megaco]
Fax and Modem detection                                          
                      f.org

                      14.01.2006 06:58

If you want to discriminate all kinds of faxes from all other
communications: Voice, modem, text telephony, then you would need a
large part of CTYP.

If you can accept to catch also modem and text telephony calls, so that
you give all data related calls more reliable transfer, then you might
be able to reduce the detail of some events.

I would guess that you would also select something more reliable than
plain
G.711 for the transport.

Gunnar
------------------------------------------------------------------------
----

-
Gunnar Hellstrom, Omnitor
[email-masked] <mailto:[email-masked]>

-----Original Message-----
From: [email-masked] [mailto:[email-masked]]On Behalf
Of Wainwright, John (Com US)
Sent: Friday, January 13, 2006 10:44 PM
To: [email-masked]
Subject: RE: [Megaco] Fax and Modem detection

Can anyone provide me with more insight into the CTYP and FTMD packages
in relationship to support of fax pass-thru via G.711 only and not using
T.38 ?
Is support of both packages and all events/signals required for this
feature ?

Thanks
John

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---

From: [email-masked]
Date: Wed, 18 Jan 2006 03:59:37 +0100

John:

>autonomous with regards to VAD/Echo cancellation

Recommend to have a look into V.152. You may see which functions are
autonomously controlled on MG level, and which are not. So, EC is NOT
automatically turn off, this is still a decision a G.168 level ("thus a
control loop entirely within the MG, not visible towards MGC"), primarily
dependent on modem type (again, have a look into V.152 and G.168).

- Albrecht

                      "Kevin Boyle"                                                                                                   
                      <[email-masked]         To:      "Wainwright, John \(Com US\)" <[email-masked]>, Albrecht         
                      om>                      SCHWARZ/DE/ALCATEL@ALCATEL, "Gunnar Hellstrom" <[email-masked]>           
                      Sent by:                 cc:      [email-masked]                                                               
                      megaco-bounces@i         Subject: RE: [Megaco] Fax and Modem detection                                          
                      etf.org                                                                                                         

                      16.01.2006 23:51                                                                                                

Kevin

-----Original Message-----
From: Wainwright, John (Com US) [mailto:[email-masked]]
Sent: Monday, January 16, 2006 5:32 PM
To: Boyle, Kevin [NCRTP:3Z40:EXCH]; [email-masked]; Gunnar
Hellstrom
Cc: [email-masked]

John

-----Original Message-----
From: Kevin Boyle [mailto:[email-masked]]
Sent: Monday, January 16, 2006 12:58 PM
To: Wainwright, John (Com US); [email-masked]; Gunnar
Hellstrom
Cc: [email-masked]

Kevin

-----Original Message-----

Thanks
John

-----Original Message-----
From: [email-masked] [mailto:[email-masked]]
Sent: Saturday, January 14, 2006 8:53 AM
To: Wainwright, John (Com US); Gunnar Hellstrom
Cc: [email-masked]
Subject: RE: [Megaco] Fax and Modem detection

John,

- Albrecht

                      "Gunnar Hellstrom"

                      Sent by:                   cc:

                      14.01.2006 06:58

Gunnar

-

-----Original Message-----

Thanks
John

---

From: Christian Groves <[email-masked]>
Date: Thu, 19 Jan 2006 10:15:05 +1100

G'Day,

Is the root of the confusion that H.248.1 E.13 defines an echo control 
property that turns an echo canceller ON or OFF, however V.152 indicates 
that the echo canceller may be disabled via a tone? From a H.248 
perspective the EC is still "ON" even though disabled.....

Regards, Christian

---

From: [email-masked]
Date: Fri, 20 Jan 2006 02:46:18 +0100

Christin,

should be no confusion: control mechanisms (incl. autonomous disabling) are
exactly identical as in TDM networks (PSTN/ISDN control triggers via call
control, overlayed by G.168 behaviour ...).
- Albrecht

                      Christian Groves                                                                                                    
                      <Christian.Groves@nt         To:      "Wainwright, John \(Com US\)" <[email-masked]>                   
                      eczone.com>                  cc:      Albrecht SCHWARZ/DE/ALCATEL@ALCATEL, Gunnar Hellstrom                         
                      Sent by:                     <[email-masked]>, [email-masked]                                         
                      megaco-bounces@ietf.         Subject: Re: [Megaco] Fax and Modem detection                                          
                      org                                                                                                                 

                      19.01.2006 00:15                                                                                                    

G'Day,

Regards, Christian

>                      <[email-masked]         To:      "Wainwright, John
\(Com US\)" <[email-masked]>, Albrecht
>                      om>                      SCHWARZ/DE/ALCATEL@ALCATEL,
"Gunnar Hellstrom" <[email-masked]>