Telephone numbering
Telephone numbers are a fundamental part of Australia's telecommunications system. 
The Telecommunications Numbering Plan 1997 (the Numbering Plan) is the set of rules that govern the administration of the numbering system, including:
- the allocation of telephone numbers and their use
- the transfer of numbers between telephone companies (known as carriage service providers or CSPs).
The Numbering Plan is administered by the Australian Communications and Media Authority (ACMA).
The allocation and use of telephone numbers
The Numbering Plan divides different types of numbers into categories. A summary of some of the more important categories follows.
Geographic numbers. Most people are already familiar with geographic numbers. They are 10-digit numbers that start with 02, 03, 07 or 08. These numbers are used for local call services in Australia, and can contain information about where a service is located. For example, by looking at the first 6 digits of the department's switch number (02 6271 1000), a consumer can see that the service is probably in the ACT (02) and in Canberra (6271).
The ACMA has recently changed the Numbering Plan to allow CSPs to give their customers 'out of area' numbers providing the CSP advises the customer:
- about the potential charging implications, given that CSPs sometimes use the geographic information in telephone numbers to decide how much to charge (for example, long distance charging)
and
- that they may have difficulty in transferring their number to a different CSP.
More information about geographic numbers and this change is available on the
ACMA Number Plan page.Mobile numbers. Mobile numbers are 10-digit numbers beginning with '04'. The ACMA allocates mobile numbers to CSPs, which in turn allocate the numbers to customers. CSPs are changed an annual numbering charge for each mobile number that they hold, to help ensure that the numbers are used efficiently.
Freephone and local rate numbers. Freephone telephone numbers begin with '1800', and local rate numbers begin with either '13' or '1300'. Freephone and local rate numbers enable the owner of the number to pay for all (in the case of freephone) or some (in the case of local rate) of a call from a geographic number. Calls from mobiles to these numbers may be charged higher rates.
Freephone and local rate numbers are allocated differently to geographic and mobile numbers. People interested in having a freephone or local rate number can either participate in an online auction for a specific number, or can contact their CSP to choose a freephone and local rate telephone number from a limited pool. Like mobile numbers, CSPs pay an annual numbering charge for each freephone and local rate number they hold. The annual numbering charge for each number is based on the number of digits. (For example, a nine-digit number is charged more than a 10-digit number). More information about freephone and local rate numbers is available on the
ACMA numbering page. Premium rate numbers. Premium rate numbers are usually 10-digit numbers beginning with '1900'. Premium rate numbers are used to provide premium services such as competitions, warranty services, adult services, financial services, psychic services and meteorology services. The cost of calls to premium rate numbers can vary between 50 cents and $5.50 per minute. Premium rate numbers are also subject to an annual numbering charge, based on the number of digits each has.
Transferring telephone numbers
The Numbering Plan enables customers to change their CSP without having to change telephone numbers. This is known as 'number portability' and enables customers to 'port' (transfer) an existing number to a new CSP without the inconvenience of having to take a new number.
Under the Numbering Plan, all CSPs must accept requests to port geographic (except paging services), mobile (except satellite services) and freephone and local rate telephone numbers. However, for technical or commercial reasons the new CSP may not be able to accept the number. When considering whether to port a service, consumers should always check with the new CSP.
Under the rules, if a consumer does port an existing number, the new CSP must provide substantially the same quality telephone service. However, the new CSP is not under an obligation to provide the same features, such as call waiting or message bank.
For more information, please see ACMA's number portability page.
