Далее редактируем файл /etc/asterisk/extensions_custom.conf
[from-BFMC]
include => from-internal-noxfer
include => from-internal-xfer
include => bad-number ; auto-generated
exten => _XXXX,1,Goto(from-internal,${EXTEN},1)
exten => _XXXXX,1,Goto(from-internal,${EXTEN},1)
exten => _XXXXXXXXXX,1,Ringing()
exten => _XXXXXXXXXX,n,Set(__RINGINGSENT=TRUE)
exten => _XXXXXXXXXX,n,Goto(from-internal,${EXTEN},1)