asterisk users - Mar 2009 - T.38 - Which endpoint shall reINVITE ? caller or callee ?

Hi,

I've been playing with T.38.

I observed that mostly but not always, it's the "calling endpoint"
that
reINVITE the other party to drop current SIP/G711 session and start a new
T.38.
But sometimes, it's also the callee party that reINVITE the calling party.

Which is the "standardized" or most common, way to start a T.38
session ?
Shall it come from callee or from caller ?

Regards
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Olivier wrote:
> Hi,
> 
> I've been playing with T.38.
> 
> I observed that mostly but not always, it's the "calling
endpoint" that
> reINVITE the other party to drop current SIP/G711 session and start a 
> new T.38.
> But sometimes, it's also the callee party that reINVITE the calling
party.
> 
> Which is the "standardized" or most common, way to start a T.38
session ?
> Shall it come from callee or from caller ?
> 
> Regards
Fax transmission can be initiated from any one of the parties. AFAIK 
T.38 as well as the PSTN fax standards do not show any preference 
whether fax transmission is requested from a or b party.

In practice, the caller usually initiates a fax transmission, but this 
doesn't mean that the called party cannot initiate it, too.

Best regards,
Vlasis Hatzistavrou.