ISDN30 Direct Dial Inward Services definition
ISDN30 Direct Dial Inward Services means the ISDN30Direct Dial Inward Planning Service, Direct Dial Inward Connection Service and the Direct Dial Inward Rental Service;
ISDN30 Direct Dial Inward Services means the ISND30 Direct Dial Inward Planning Service, ISDN30 Direct Dial Inward Connection Service and the ISDN30 Direct Dial Inward Rental Service or the Existing ISDN30 Direct Dial Inward Rental Service, giving recipients of the services the capability to allow incoming calls to be routed directly rather than routing via a central switchboard number;