Re: [Megaco] Fax and Modem detection

I'll add that the most common modems are described in 
draft-ietf-avt-rfc2833bisdata-05.txt.  Most of the startup sequences 
seem to have ANS or ANSam in common at the called end, but you can't 
count on the calling end to emit any specific tone to start with.

Boyle, Kevin [NCRTP:3Z40:EXCH] wrote:
> Most faxes do start with CNG.  Modems start with one of several
> possible, of which you have described some.  I suggest having a look at
> the relevant modem specs, which are found in the ITU-T V-series
> Recommendations.
>  
> Kevin
> 
> 
> ________________________________
> 
> 	From: megaco-bounces@ietf.org [mailto:megaco-bounces@ietf.org]
> On Behalf Of Tamar Nemet
> 	Sent: Tuesday, December 20, 2005 5:15 AM
> 	To: megaco@ietf.org
> 	Cc: Shai Antebi; Michal Yachimovitz; Victoria Mendelevich; Moiz
> Terem; Rima Mazorov
> 	Subject: [Megaco] Fax and Modem detection
> 	
> 	
> 	 
> 	Hello,
> 	 
> 	The ftmd (FAX/Textphone/Modem Tones Detection) package defines
> many events to detect the presence of data traffic (fax, modem) on a
> line.
> 	Which event should be used in order to notify the SoftSwitch
> that a fax or modem has been detected ?
> 	 
> 	It looks that CNG should be used in case of fax. But for modem
> there are a lot of events. Does the Media Gateway must detect all kinds
> of modem signals and send the exact modem event to the SoftSwitch ?
> (V21flag,CIV18, XCI,CIdata,V21Tone,V23tone ....)
> 	Or there is a generic event for modem detection ?
> 	 
> 	Thanks,
> 	Tamar Nemet
> 	 
> 
> 
> 
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> 
> 

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