For example, a "psychic hotline" type of 1-900 number may charge .99 for the first minute and 99 cents for each additional minute.
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.
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").
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.
One variant, targeted at children too young to dial a number, enticed children to hold the phone up to the television set while the DTMF tones of the number were played.
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.
Unlike a normal call, part of the call charge is paid to the service provider, thus enabling businesses to be funded via the calls.