Vertical service code
Encyclopedia
A vertical service code or VSC is a special code dialed prior to (or instead of) a telephone number
that engages some type of special telephone service. Typically preceded with an asterisk
, or * (star), key on the touch tone keypad and colloquially referred to as star codes, most are two digits in length although, as more services are developed, those that use 2 or 3 as the first digit are sometimes three digits in length.
In North American
telephony
, VSCs were developed by AT&T as Custom Local Area Signaling Services or CLASS codes (or LASS) in the 1960s and 70's. Their use became ubiquitous throughout the 1990s and eventually became a recognized standard. As CLASS was an AT&T
trademark, the moniker of Vertical service codes was adopted by the North American Numbering Plan Administration. The use of the word "vertical" is a somewhat arcane tip of the hat to older switching methods and the fact that these services can only be accessed by a local telephone subscriber; going up (or vertically) inside the local central office instead of out to another telephone company.
by dialing 11 instead of the * prior to the code (1167 instead of *67 will typically work on any North American telephone to enable Caller ID privacy), or on some carriers, by dialing the code alone (activating after a pause). Because of historical usage by some telephone switch
manufacturers, in some areas VSCs may also be dialed by placing a # (hash or pound key) after the code, instead of a * before it (72# instead of *72 for Call Forwarding).
GSM cellular telephone carriers provide codes
similar to VSCs using a # as the leading character. Because these pound codes are not part of the NANPA
system, they are not considered Vertical Service Codes. However, many NANPA VSCs have also been adopted by cellular carriers (e.g., 72 for forwarding, 67 for Caller ID blocking), and some VSCs were created specifically for mobile carriers (such as 228 and 272). cdmaOne
carriers in North America use only VSCs.
. Not all of these services are available in all areas, and some are only available to landline
or cellular
telephones. Some require additional services be purchased from the telephone company
to use them.
Local Area Signalling Services (LASS) and Custom Calling Feature Control Codes:
Telephone number
A telephone number or phone number is a sequence of digits used to call from one telephone line to another in a public switched telephone network. When telephone numbers were invented, they were short — as few as one, two or three digits — and were given orally to a switchboard operator...
that engages some type of special telephone service. Typically preceded with an asterisk
Asterisk
An asterisk is a typographical symbol or glyph. It is so called because it resembles a conventional image of a star. Computer scientists and mathematicians often pronounce it as star...
, or * (star), key on the touch tone keypad and colloquially referred to as star codes, most are two digits in length although, as more services are developed, those that use 2 or 3 as the first digit are sometimes three digits in length.
In North American
North American
North American generally refers to an entity, people, group, or attribute of North America, especially of the United States and Canada together.-Culture:*North American English, a collective term used to describe American English and Canadian English...
telephony
Telephony
In telecommunications, telephony encompasses the general use of equipment to provide communication over distances, specifically by connecting telephones to each other....
, VSCs were developed by AT&T as Custom Local Area Signaling Services or CLASS codes (or LASS) in the 1960s and 70's. Their use became ubiquitous throughout the 1990s and eventually became a recognized standard. As CLASS was an AT&T
AT&T
AT&T Inc. is an American multinational telecommunications corporation headquartered in Whitacre Tower, Dallas, Texas, United States. It is the largest provider of mobile telephony and fixed telephony in the United States, and is also a provider of broadband and subscription television services...
trademark, the moniker of Vertical service codes was adopted by the North American Numbering Plan Administration. The use of the word "vertical" is a somewhat arcane tip of the hat to older switching methods and the fact that these services can only be accessed by a local telephone subscriber; going up (or vertically) inside the local central office instead of out to another telephone company.
Other dialing formats
In most cases VSCs can also be accessed from rotary phonesPulse dialing
Pulse dialing, dial pulse, or loop disconnect dialing, also called rotary or decadic dialling in the United Kingdom , is pulsing in which a direct-current pulse train is produced by interrupting a steady signal according to a fixed or formatted code for each digit and at a standard pulse repetition...
by dialing 11 instead of the * prior to the code (1167 instead of *67 will typically work on any North American telephone to enable Caller ID privacy), or on some carriers, by dialing the code alone (activating after a pause). Because of historical usage by some telephone switch
Telephone exchange
In the field of telecommunications, a telephone exchange or telephone switch is a system of electronic components that connects telephone calls...
manufacturers, in some areas VSCs may also be dialed by placing a # (hash or pound key) after the code, instead of a * before it (72# instead of *72 for Call Forwarding).
GSM cellular telephone carriers provide codes
GSM codes for supplementary services
Global System for Mobile Communications standards define certain codes that make it possible to query and set certain service parameters from mobile devices...
similar to VSCs using a # as the leading character. Because these pound codes are not part of the NANPA
Nanpa
, also transliterated as nampa, in Japanese culture is a type of flirting and seduction popular among teenagers and people in their twenties and thirties. When Japanese women pursue men in a fashion similar to nanpa, it is called .-Etymology:...
system, they are not considered Vertical Service Codes. However, many NANPA VSCs have also been adopted by cellular carriers (e.g., 72 for forwarding, 67 for Caller ID blocking), and some VSCs were created specifically for mobile carriers (such as 228 and 272). cdmaOne
IS-95
Interim Standard 95 is the first CDMA-based digital cellular standard by Qualcomm. The brand name for IS-95 is cdmaOne. IS-95 is also known as TIA-EIA-95....
carriers in North America use only VSCs.
List of vertical service codes
The following are the VSCs generally used in the North American Numbering PlanNorth American Numbering Plan
The North American Numbering Plan is an integrated telephone numbering plan administered by Neustar which encompasses 24 countries and territories, including the United States and its territories, Canada, Bermuda, and 16 nations of the Caribbean...
. Not all of these services are available in all areas, and some are only available to landline
Landline
A landline was originally an overland telegraph wire, as opposed to an undersea cable. Currently, landline refers to a telephone line which travels through a solid medium, either metal wire or optical fibre, as distinguished from a mobile cellular line, where transmission is via radio waves...
or cellular
Mobile phone
A mobile phone is a device which can make and receive telephone calls over a radio link whilst moving around a wide geographic area. It does so by connecting to a cellular network provided by a mobile network operator...
telephones. Some require additional services be purchased from the telephone company
Telephone company
A telephone company is a service provider of telecommunications services such as telephony and data communications access. Many were at one time nationalized or state-regulated monopolies...
to use them.
Local Area Signalling Services (LASS) and Custom Calling Feature Control Codes:
| Service | Tone | Pulse/rotary | | Notes |
|---|---|---|---|
| Cancel forwarding | 30 | n/a | [C1] |
| Automatic Forwarding | 31 | n/a | [C1] |
| Notify | 32 | n/a | [C1] [2] |
| Intercom Ring 1 (short short) | 51 | 1151 | [3] |
| Intercom Ring 2 (short short long) | 52 | 1152 | [3] |
| Intercom Ring 3 (short long short) | 53 | 1153 | [3] |
| Extension Hold | 54 | 1154 | [3] |
| Customer Originated Trace | 57 | 1157 | |
| Selective Call Rejection (or Call Screen) | 60 | 1160 | |
| Selective Distinct Alert | 61 | 1161 | |
| Selective Call Acceptance | 62 | 1162 | |
| Selective Call Forwarding | 63 | 1163 | |
| ICLID Activation | 65 | 1165 | |
| Busy Number Redial | 66 | 1166 | |
| Number Display Blocking | 67 | 1167 | [4] |
| Computer Access Restriction | 68 | 1168 | |
| Call Return (incoming) | 69 | 1169 | |
| Call Waiting Call waiting Call waiting , in telephony, is a feature on some telephone networks. If a calling party places a call to a called party which is otherwise engaged, and the called party has the call waiting feature enabled, the called party is able to suspend the current telephone call and switch to the new... disable |
70 | 1170 | [4] |
| No Answer Call Transfer | 71 | 1171 | |
| Usage Sensitive 3 way call | 71 | 1171 | |
| Call Forwarding Call forwarding Call forwarding , in telephony, is a feature on some telephone networks allowing an incoming call to a called party to be redirected to a third party. For example, the third party may be a mobile telephone, voicemail box or other telephone number where the desired called party is situated. It was... : start |
72 | 1172 | |
| Call Forwarding: cancel | 73 | 1173 | |
| Speed Calling Speed calling Speed Calling service allows telephone subscribers to assign one or two digit speed calling codes, by dialing a change speed calling list access code, a feature code, and a new telephone number. Thereafter, the subscribers need only use the assigned speed code to reach the desired party rather... (8 numbers) |
74 | 1174 | |
| Speed Calling (30 numbers) | 75 | 1175 | |
| Anonymous Call Rejection Anonymous call rejection The codes described are relevant only to the NANP telephone system. A similar feature is used in European ISDN networks, which is mandated by the European Telecommunication Regulation in the Directive on Privacy and Electronic Communications, cf. wikipedia .... |
77 | 1177 | [5] [M: *58] |
| Call Screen Disable | 80 | 1180 | (or Call Screen) [M: *50] |
| Selective Distinct Disable | 81 | 1181 | [M: *51] |
| Number Display Unblocking | 82 | 1182 | [4] [7] |
| Select. Forwarding Disable | 83 | 1183 | [M: *53] |
| Caller ID Caller ID Caller ID , also called calling line identification or calling number identification or Calling Line Identification Presentation , is a telephone service, available in analog and digital phone systems and most Voice over Internet Protocol applications, that transmits a caller's number to... Disable |
85 | 1185 | |
| Busy Number Redial Cancel | 86 | 1186 | [6] [M: *56] |
| Anonymous Call Rejection Disable | 87 | 1187 | [5] [M: *68] |
| Call Return Cancel | 89 | 1189 | [6] [M: *59] |
See also
- Prompt voice for most U.S. AT&TAT&TAT&T Inc. is an American multinational telecommunications corporation headquartered in Whitacre Tower, Dallas, Texas, United States. It is the largest provider of mobile telephony and fixed telephony in the United States, and is also a provider of broadband and subscription television services...
implementations of VSC features is Pat FleetPat FleetPat Fleet is a working American voice actress known as the registered voice of AT&T.Widely recognized for the tens of thousands of recordings she has made for US telephone companies such as AT&T, Verizon, Qwest, the former Bell System companies, and others since 1981, she is still most recognized... - Mobile dial codeMobile dial codeA Mobile Dial Code is a phone number that allows the request and receipt of information directly to a mobile phone.A Mobile Dial Code combines a toll-free number, a web address and a short code into one simplified number. It is a 2-12 digit string of letters or numbers that is preceded by a...