Telephone numbers in Australia plan (including the "Trunk Access Code"), presented in domestic format. (Geographical region boundaries do not exactly follow State borders.) The current numbering plan would appear to be sufficient to cope with potential increase in demand for services for quite some time to come. The 06 and 09 area codes are completely unused. In addition, each current area code has large number "ranges" unallocated. When dialling from outside Australia, after dialling the appropriate International Access Code it is necessary to dial the Country Code for Australia (61) followed by the nine digit "National 'Significant' Number". (The + symbol is used to
International direct dialing International direct dialing International direct dialing (IDD) or international subscriber dialling (ISD) is placing an international telephone call that is dialed directly by a telephone subscriber, rather than by an telephone operator. The term "international subscriber dialling" was used in the United Kingdom and Australia until the terminology was changed to international direct dialling. Since the late 20th century, most international calls are dialed directly. Calls are initiated by dialing the international call prefix for the originating country, followed by the country calling code for the destination country, and finally the national telephone number of the destination. When phone numbers