Numbers with the 900 area code were those which were expected to have a huge number of potential callers, and the 900 area code was screened at the local level to allow only a certain number of the callers in each area to access the nationwide long distance network for reaching the destination number.Also, the early incarnation of 900 was not billed at premium-rate charges, but rather at regular long distance charges based on the time of day and day of week that the call was placed.Due to complaints from parent groups about kids not knowing the dangers and high cost of such calls, the FTC enacted new rules and such commercials ceased to air on television as of the mid-1990s.

This practice continues, along with the use of these numbers for things such as software technical support, banking access, and stock tips.

Adult entertainment 900 numbers have been largely absent from AT&T and MCI since 1991.

A call to either one of these numbers can result in a high per-minute or per-call charge.

For example, a "psychic hotline" type of 1-900 number may charge $2.99 for the first minute and 99 cents for each additional minute.

While the billing is different, calls are usually routed the same way they are for a toll-free telephone number, being anywhere despite the area code used.

These telephone numbers are usually allocated from a national telephone numbering plan in such a way that they are easily distinguished from other numbers.

In 1992, the Supreme Court allowed a law passed by Congress that created a block on all 900 numbers that provided adult content, except for those consumers who requested access to a specific number in writing.

The law killed the adult 900 number business, which moved over to 800 numbers, where billing had to be done by credit card.

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.