Telephone dialing code for access to service features
A vertical service code (VSC) is a sequence of digits and the signals star (*) and pound/hash (#) dialed on a telephone keypad or rotary dial to access certain telephone service features.[1] Some vertical service codes require dialing of a telephone number after the code sequence. On a touch tone telephone, the codes are usually initiated with the star key, resulting in the commonly used name star codes. On rotary dial telephones, the star is replaced by dialing 11.
In North Americantelephony, VSCs were developed by the American Telephone and Telegraph Company (AT&T) as Custom Local Area Signaling Services (CLASS or LASS) codes in the 1960s and 70s. Their use became ubiquitous throughout the 1990s and eventually became a recognized standard. As CLASS was an AT&T trademark, the term vertical service code was adopted by the North American Numbering Plan Administration. The use of vertical is a somewhat dated reference to older switching methods and the fact that these services can only be accessed by a telephone subscriber, going up (vertically) inside the local central office instead of out (horizontally) to another telephone company.
Feature definitions
The following are the vertical service codes generally recommended by the North American Numbering Plan Administrator for use in the NANP territories. Not all of these services are available in all areas, and some are only available on landline telephones or Mobile phones.
Local Area Signalling Services (LASS) and Custom Calling Feature Control Codes:[1][2][3]
Vertical service code
Service definition
Australia
Japan
UK
Tone dialing
Pulse dialing
*51
1151
Who called me. Provides the directory number, date and time of unanswered calls.
*52
1152
Call Hold (Single Line Variety Package). Permits the call to be picked up at another station.
*53
1153
Distinctive Ring B. Allows a subscriber to alert a specific party distinctively.
*54
1154
Distinctive Ring C. Allows a subscriber to alert a specific party distinctively.
^1361 to get number, 1363 to call back. "NewsRelease". NTT East. Retrieved June 20, 2013. "Number OSIRASE 136". NTT West. Retrieved June 20, 2013.
^After dialing 1471, the caller can press "3" to automatically return the call. Previously free, since August 2004 the return call service incurs a charge.
