Vertical service code: Difference between revisions

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{{Short description|CodesTelephone dialing code for localaccess telephoneto functionsservice features}}<!-- better than nothing, but please improve it if you can -->

{{use American English|date=September 2022}}

{{use MDY dates|date=September 2022}}

A '''vertical service code''' ('''VSC''') is a sequence of digits and the signals [[asterisk|star]] (*) and [[number sign|pound/hash]] (#) dialed on a [[telephone keypad]] or [[rotary dial]] to enable or disableaccess certain telephone service features.<ref name=":0" /> 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 [[Asterisk#Telephony|star key]], resulting in the commonly used name ''star codes''. On rotary dial telephones, the star is replaced by dialing ''11''.

{{Expand German}}

A '''vertical service code''' ('''VSC''') is a sequence of digits and the signals [[asterisk|star]] (*) and [[number sign|pound/hash]] (#) dialed on a [[telephone keypad]] or [[rotary dial]] to enable or disable certain telephone service features.<ref name=":0" /> 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 [[Asterisk#Telephony|star key]], resulting in the commonly used name ''star codes''. On rotary dial telephones, the star is replaced by dialing ''11''.

In [[North American]] [[telephony]], VSCs were developed by the [[AT&TAmerican Corp.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 local telephone subscriber, going up (''vertically'') inside the local [[telephone exchange|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 AdministrationAdministrator]] for use in the NANP territories. Not all of these services are available in all areas, and some are only available toon [[landline]] telephones or [[Mobile phone|cellular]] telephoness.

===North America & elsewhere===

The following are the vertical service codes generally recommended by the [[North American Numbering Plan Administration]] for use in the NANP territories. Not all of these services are available in all areas, and some are only available to [[landline]] or [[Mobile phone|cellular]] telephones.

Local Area Signalling Services (LASS) and Custom Calling Feature Control Codes:<ref>{{Cite magazine|title=The #hack FAQ|url=http://www.phrack.com/issues.html?issue=47&id=7|author=voyager|editor=Erik Bloodaxe|magazine=Phrack Magazine|page=7|date=1995-04-15|access-date=2013-03-18}}</ref><ref name=":0">{{Cite web|title=Vertical Service Codes – Code Definitions|url=https://nationalnanpa.com/number_resource_info/vsc_definitions.html|publisher=North American Numbering Plan Administrator|work=NationalNANPA.com|access-date=2022-07-30}}</ref><ref>{{Cite web|title=Vertical Service Codes – Code Assignments|url=http://www.nanpa.com/number_resource_info/vsc_assignments.html|publisher=Neustar|work=NANPA.com|access-date=2013-03-18}}</ref>