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 American telephony, 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:[2][1][3]

Vertical service codeService definitionAustraliaFranceIsraelJapanUK
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.
*57 1157 Call trace (Malicious caller identification)
*60 1160 Call blocking
*61 1161 Priority call
*62 1162 Selective call waiting
*63 1163 Selective call forwarding
*65 1165 Calling number delivery activation
*66 1166 Continuous redial
*67 1167 Calling number delivery blocking 1831
#31#[4][5]
141
#31#[6]
*68 1168 Activate call forwarding on busy
*69 1169 Last-call return (incoming) *69 HFC
*10#[7][8]
3131 *42 1361
1363[9]
1471[10]
*70 1170 Call waiting disable
*71 1171 Usage sensitive three-way call
*72 1172 Unconditional forward: All calls
*73 1173 Call forward: Cancel
*74 1174 Speed calling (8 numbers)
*75 1175 Speed calling (30 numbers)
*77 1177 Anonymous call rejection activation
*78 1178 Do not disturb
*79 1179 Do not disturb disable
*80 1180 Call blocking disable
*81 1181 Priority call disable
*82 1182 Caller ID (per call) *31#/1832[11] 1470
*83 1183 Selective call forwarding disable
*85 1185 Caller ID disable
*86 1186 Continuous redial cancel
*87 1187 Anonymous call rejection deactivation
*88 1188 Deactivate call forwarding on busy
*89 1189 Last-call return cancel
*90 1190 Conditional forward: Busy line
*92 1192 Conditional forward: No answer
*94 1194 Directed call pickup
*272 Wireless Priority Service

See also

telephone icon Telephones portal

References

  1. 1 2 "Vertical Service Codes – Code Definitions". NationalNANPA.com. North American Numbering Plan Administrator. Retrieved July 30, 2022.
  2. voyager (April 15, 1995). Erik Bloodaxe (ed.). "The #hack FAQ". Phrack Magazine. p. 7. Retrieved March 18, 2013.
  3. "Vertical Service Codes – Code Assignments". NANPA.com. Neustar. Retrieved March 18, 2013.
  4. 1831 on landlines, or #31# from a mobile
  5. "HOW TO: block your number when calling someone". Telstra Exchange. Telstra. Retrieved May 28, 2017.
  6. 141 on landlines and #31# on mobiles
  7. *69 on Optus HFC Telephony network. "Optus Personal – Using Call Return" This only allows one to return the last unanswered call, and can cost 35 cents per use.
  8. 1361 to get number, 1363 to call back. "NewsRelease". NTT East. Retrieved June 20, 2013. "Number OSIRASE 136". NTT West. Retrieved June 20, 2013.
  9. 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.
  10. 1832 on landlines, or *31# from a mobile

Public Domain This article incorporates public domain material from Federal Standard 1037C. General Services Administration. Archived from the original on January 22, 2022.

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