Yes, this is possible, but needs some modification: 1) For versions BC7,8,9,10 there is a patch, BC11 needs a license + a patch, in BC12 a license is needed
2) For ELU11/ELU21 boards some strapping and cutting is needed (no actve sustaining, so no source code available for the HW any more). For ELU29 a PROM change is needed. NOTE! ELU29/1 is NOT supported!
The functionality is controlled by ICAT parameter just in order not to load the system in case some phone does not have this function.
This works with internal and external lines (if they are sending the AID). The function slows down the incoming call sequence for about 1-4s, depending of how many digits we are receiving (max is 10 in this patch). The telephone has to support DTMF.
Anybody really interested can put his Email on the forum in order to get more information.