[asterisk-users] Ring back when free?

[Yehavi Bourvine +972-8-9489444]

> Has anyone here implemented "Ring back when free" in Asterisk?

Here is what I do; the dialplan enclosed is in AEL2 format, but you can get the
idea.

When a call is originated I save the called and callee numbers in a database.
If the user gets busy he/she hangs up and dial *41. I then retreive the last
number they dialled and place a flag in the database that someone is camping on
it. The H extension checks this flag and if found generates a .call file.

First, I have a macro to save the for each extension who is the last they
called and the last who called them:

// Save the calling and called numbers in To and From and in the database so
// they can be used by *41 and *42. This way the h extension can acecss this
// database for all destinations.
        macro Save_From_to ( ) {
// To and From are used in the dialplan, since we might change ${EXTEN}
                Set(_To=${MACRO_EXTEN});
                Set(_From=${CALLERID(num)});
                NoOp("===== ${From} -> ${To});
// Save them in database for later use.
// Save the caller number at the called extension for *42 usage.
                Set(DB(${To}/LastCaller)=${From});
// Where we called for *41
                Set(DB(${From}/LastCalled)=${To});
        };


This macro is called at the beginning of the "normal" dialplan.

Now, the *41 which registers the "camp-on" using the data saved above:
// *41: Camp on the last extension dialled
        *41 => {
                Set(tmp=${DB(${CALLERID(num)}/LastCalled)});
// Save it so when the other side hangs it will see it and dial us.
                Set(DB(${tmp}/CallBack)=${CALLERID(num)});
// Say the number to caller so he can verify...
                SayDigits(${tmp});
                Hangup();
        };

And now the H extension for handling it:

// The Hangup extension which is called when the call is hanged. See whether
// we have some waiting callback waiting on this extension.
        h => {
                ResetCDR(w);    // To make the CDR correct.
                NoOp(${From});

// We have to check the two sides of the call: Those who camp on the calling
and
// those who camp on the called.
                Set(tmp=${DB(${From}/CallBack)}); // The calling.
                if("${tmp}" != "") {    // Something is there.
                        DBdel(${From}/CallBack); // And delete it...
// Create the callfile and then move it to the spool directory to make the
call.
                        System(echo Channel:  SIP/${tmp} >
/tmp/test.tmp${From})
;
                        System(echo WaitTime: 20 >> /tmp/test.tmp${From});
                        System(echo Extension: ${From} >>
/tmp/test.tmp${From});
                        System(echo CallerID: Callback \\\<${tmp}\\\> >>
/tmp/te
st.tmp${From});
                        System(mv /tmp/test.tmp${From}
/var/spool/asterisk/outgo
ing/);
                };

                Set(tmp=${DB(${To}/CallBack)}); // The called
                if("${tmp}" != "") {    // Something is there
                        DBdel(${To}/CallBack); // And delete it...
// Create the callfile and then move it to the spool directory to make the
call.
                        System(echo Channel:  SIP/${tmp} > /tmp/test.tmp${To});
                        System(echo WaitTime: 20 >> /tmp/test.tmp${To});
                        System(echo Extension: ${To} >> /tmp/test.tmp${To});
                        System(echo CallerID: Callback \\\<${tmp}\\\> >>
/tmp/te
st.tmp${To});
                        System(mv /tmp/test.tmp${To}
/var/spool/asterisk/outgoin
g/);
                };
        };


                  Good luck!  __Yehavi: