areas. This former alphanumeric scheme was significantly different from the current system used for SMS messages. The former alphanumeric scheme was: A = 1; B = 2; F = 3; J = 4; L = 5; M = 6; U = 7; W = 8; X = 9; Y = 0 The letters did not relate to any exchange name. For example, the exchange prefix for Essendon was FU (which translated to 37 and later became the 37x [then 937x] exchange used by the whole City of Essendon [which became the City of Moonee Valley in late 1994]). Although Melbourne city numbers began with 6, it was only rarely, and probably by accident, that any other exchanges had matching letters. Numbers using the old alphanumeric scheme were written as ab.xxxx, for example FU 1234 (the actual train of digits sent to the phone was "371234") or MW 5550 (685550). Seven-digit numbers started appearing as early as 1960, and were all numerical from the start. There were still some six-digit numbers and at least one five-digit number in Melbourne as late as 1989, but by the 1990s, they all had been converted to seven-digit numbers. Footscray used six-digit numbers in exchange code 68 until 1987, when they were changed to 687 or 689. The old call back number was 199, and could be used on public payphones, and private numbers too. This was moved to a new number 12722199. See also Former Australian dialling codes Telecommunications in Australia References ITU allocations list External links List of Telephone Exchanges Excel file of exchange prefixes via Telstra Wholesale site Telecommunications Numbering Plan 1997 Telecommunications Numbering Plan 2015 All Areas by Prefix (archive.org snapshot of old version of official site) All Areas by Prefix (official site - expand heading Geographic numbers) All Areas by Prefix (ATO) Australia Phone Number Australia Australia communications-related lists