Area Code 900 went into service January 1, 1971, but the first known to have been used in the United States for the "Ask President Carter" program in March 1977, for incoming calls to a nationwide talk radio broadcast featuring the newly elected President Jimmy Carter, hosted by anchorman Walter Cronkite.At that time, the intent for area code 900 was as a choke exchange—a code that blocked large numbers of simultaneous callers from jamming up the long distance network.The number used for the radio program was one that was specially arranged by AT&T Corporation, CBS Radio, and the White House, to be free to the calling party.the 900 area code was completely restructured by AT&T to be the premium-rate special area code which it remains today.This type of scam was especially popular in the late '80s to early '90s in the United States before tougher regulations on the 900 number business forced many of these businesses to close.A 1-900 telephone number, in the North American Numbering Plan, has the form 1-900-###-####, and is often called a 900 number or a 1-900 number ("one-nine-hundred").
One scheme involved inducing users to download a program known as a dialer that surreptitiously dialed a premium-rate number, accumulating charges on the user's phone bill without their knowledge.
Earlier, 976 numbers used 976 as a local prefix (970 or 540 in some markets like New York state), though it was not assigned to a specific telephone exchange like other prefixes.
These numbers were dialed as any other number, such as 976-1234.
Adult chat lines (phone sex) and tech support are a very common use of premium-rate numbers.
Other services include directory enquiries, weather forecasts, competitions and voting (especially relating to television shows).