[asterisk-dev] Set and get Information Elements (IE)

[Richard Mudgett]

> >> I have two asterisks connected via PRI. (Current Version is 1.8
> >> and
> >> the
> >> card is a Digium TE410 using DAHDI)
> >> The objective is to pass Meta-information with the call. When I
> >> take
> >> a
> >> look at Q.SIG, EUROISDN / DSS1 and so on
> >> there is the possibility for using "userfields" e.g. UUS1. All
> >> these
> >> information are protocolled as Information Elements.
> >> When I trace the ISDN Communication (pri intense debug...) I can
> >> see
> >> und
> >> understand some "standard" IEs.
> >> Is it possible (and if, how) to set and get the standard / my own
> >> IEs
> >> for transferring (very little / some bytes) of
> >> binary extra information during the dial / call-setup? I cannot
> >> use
> >> the
> >> callerid to transmit this information..
> >
> > You cannot get/set arbitrary IEs with Asterisk/libpri.  The closest
> > you
> > can get with the current architecture is the user-user IE.  Support
> > for
> > it is normally conditionaled out and it is setup for null
> > terminated strings
> > instead of arbitrary binary data.  You might also consider passing
> > this
> > information as a subaddress if you control both sides.
> >
> > Richard
> >
> >
> Hello Richard,
> 
> thanks for your answer.  Can you tell me, how to use / control / set
> /
> get the subadress ?

You have access to subaddress information using the CALLERID and CONNECTEDLINE
dialplan functions.  For completeness, also the REDIRECTING function.  However,
the messages containing redirecting information do not exchange redirecting
subaddresses.

> Do I understand the specs right, that the subaddress may be 20 chars
> long and may be
> alphanumeric ? This would be an option..
> 
> Same applies for user-user-IE... I already mentioned this IE in my
> first
> post, but I absolutely
> don´t know how to set and get this IE... What do you mean with
> "normally
> conditionaled out"?

You have to edit channels/sig_pri.c and define SUPPORT_USERUSER for the
code that handles the user-user information to be in the compiled code.
To get/set the user-user information is via the channel variable USERUSERINFO.
Since it is normally not compiled into the code it has very little testing.

Richard