702 ABC Sydney (official call sign: 2BL) is an ABC radio station in Sydney, Australia. It is the flagship station in the ABC Local Radio network and broadcasts on 702 kHz on the AM dial. The station transmits with a power of 50,000 Watts (the maximum permissible in Australia) from a site 30 kilometres west of the Sydney CBD. 
702 ABC Sydney was the first full-time radio station in Australia, having commenced broadcasting on 23 November 1923. Its first callsign was 2SB where 2 denotes the State of New South Wales and SB stood for Broadcasters (Sydney) Limited. However, the callsign was soon altered to 2BL for Broadcasters (Sydney) Limited.
2BL became one of the inaugural stations in the ABC network when it was founded in 1932 along with sister station 2FC. In 1946, it became the flagship of the National Programme, forerunner of Radio National. It also began carrying parliamentary broadcasts. In 1963, it swapped formats with 2FC and assumed that station's old role as flagship of the Interstate Programme, which eventually evolved into Local Radio. However, it continued to air parliament until 1988. 2BL was re-branded as 702 ABC Sydney in 2000.
In the second radio ratings survey of 2012, Nielsen Media Research recorded 702's share of the Sydney radio market as the second largest at 10.3%, behind commercial talk station 2GB.
Most Local Radio stations in New South Wales simulcast 702's programming when not airing local shows for their areas. The exception is 999 ABC Broken Hill, which relays 891 ABC Adelaide due to Broken Hill being on Central Time.
^The station never used the callsign 2BS, although this is quoted in a reputedly reputable source - Changing Stations. The Story of Australian Commercial Radio Griffen-Foley, Bridget, Sydney, 2009. (The callsign 2BS was later used by the local Bathurst station).