 The last four digits are usually chosen by the station to be their callsign or frequency, or their moniker if it is short (such as B937 (2937) for a fictional B-93.7 FM).When used on a radio or television program carried on a broadcast network, such a number is usually a toll-free telephone number, without a special number since it simply redirects to a local request line circuit.This allows anyone to call regardless of the location, even from a payphone.