Asterisk 11 on a CentOS6, no add-ons, several models of SIP phones
call-waiting is enabled on all call-limit>1 (2,3,10 - depending on the model), was
as a friend, all normally accepted second call, hold call; even the BLF works...
The model Panasonic KX-UT133 - when the subscriber is talking, attempt to score causes it...