特殊电话号码功能 - Vertical service code(zt)

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Vertical service code

From Wikipedia, the free encyclopedia

In North American telephony, a vertical service code or VSC is a special code dialed prior to 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.

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.


Other dialing formats

In most cases VSCs can also be accessed from rotary phones 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.

List of vertical service codes

The following are the VSCs generally used in the North American Numbering Plan. 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.

*00 English, *01 French - Inward Voice Activated Services (IVAS) enables a subscribing business to provide automated voice activated routing for inbound English or French speaking calls (i.e., separate codes for the same service in each language). IVAS will initially consist of the following services:

  • Voice Activated Premier Dialing (VAPD) which allows customers to contact subscribing businesses by speaking the business name or service.
  • Voice Activated Blue Pages (VABP) which allows customers to request access to government services.
  • Voice Activated Auto Attendant (VAAA) which provides enhancements to Auto Attendant applications by providing a voice recognition interface in place of Touch Tone.
  • Voice Activated Audio Text (VAAT) provides users ability to request specific information from a business.
  • Voice Activated Interactive Voice Response (VAIVR) which allows the caller to interact with a subscriber's specific application in a prescribed manner.

  • *02 - Deactivation/Activation of In-Session Activation (ISA) on a per line basis - Allows a subscriber to deactivate or activate (i.e., toggle) the In-Session Activation feature on a per line basis. ISA is a feature that gives the caller a menu of call completion services using voice prompts when the call encounters a busy or no-answer condition.
  • *03 - Deactivation/Activation of In-Session Activation (ISA) on a per call basis - Allows a subscriber to deactivate the In-Session Activation feature on a per call basis. When the call is completed, ISA reverts back to the active state. ISA is a feature that gives the caller a menu of call completion services using voice prompts when the call encounters a busy or no-answer condition.
  • *40 - Change Forward-To Number for Customer/Programmable Call Forwarding Busy Line - Access Code followed by directory number is used to change the forwarded-to number for Call Forwarding Busy Line (CFBL). The state of CFBL is not changed when this access code is used. This feature will utilize the activation code of *90 and deactivation code *91 with the following exceptions: activation will not require/allow the identification of a forwarded-to directory number and deactivation will not clear the forwarded-to directory number.
  • *41 - Activation Six-Way Conference Calling - Allows the subscriber to originate a six-way conference call. Customers will enter this code prior to the first directory number added into the conference. Each subsequent member of the conference is added with a flash hook. This code is used to eliminate action conflicts with other flash hook originated features.
  • *42- Change Forward-To Number for Customer Programmable Call Forwarding Don't Answer - Access Code followed by directory number is used to change the forwarded-to number for Call Forwarding Don't Answer (CFDA). The state of CFDA is not changed when this access code is used. This feature will utilize the activation code of *92 and deactivation code *93 with the following exceptions: activation will not require/allow the identification of a forwarded-to directory number and deactivation will not clear the forwarded-to directory number.
  • *43 - Drop last member of Six-Way Conference Call - Provides the subscriber establishing a six-way conference to terminate the last party added to the call. This frees the port for an additional party when the last party wasn't reachable.
  • *44 - Voice Activated Dialing - Access to the Voice Activated Dialing (VAD) directory. Customers will dial this code to access their VAD directory in order to add, delete or review the names and numbers
  • *45 - Extended Dial Tone - Extend dial tone for Voice Activated Dialing (VAD). Customers will dial this code to extend the length of time in which dial tone is heard after going off-hook so that various Customer Premise Equipment (CPE, i.e., fax and modems) will work properly.
  • *46 - French Voice Activated Network Control - Provides the subscriber access to Voice Activated Network Control (VANC) via the French language. Subscribers will dial this code to access VANC so that they can say a name or command in French that will be activated, deactivated or provide access to a service, e.g., Call Forwarding, Call Trace, etc.
  • *47 - Override Feature Authorization - Allows a subscriber to override a Feature Authorization activated on a line which restricts 1+ calls from that line. Feature Authorization may be overridden by dialing *47 and a Personal Identification Number (PIN) and then dialing a 1+ call after receiving a second dial tone.
  • *48 - Override Do Not Disturb - Allows a subscriber to override the Do Not Disturb feature which has been activated on a line. After receiving a message indicating the station is in a Do Not Disturb condition, the subscriber may override the condition by dialing *48 and then a Personal Identification Number (PIN) thus allowing the call to be completed in the normal manner.
  • *49 - Long Distance Signal - Extended period activation/deactivation (toggle) of basic 1FR/1MR long distance signal ringing/call waiting tones.
  • *50 - Voice Activated Network Control - Access to Voice Activated Network Control (VANC). Customers will dial this code to access VANC so that they can say a name or command that will be activated, deactivated or to access a service.
  • *51 - Who Called Me? - Provides the subscriber with the directory number (DN), date, and time of unanswered calls.
  • *52 - Call Hold - Single Line Variety Package (SVP) : Gives the subscriber the capability of placing a call on hold so that the call may be continued from another extension.
  • *53 - Distinctive Ring B - Single Line Variety Package (SVP) : Allows a subscriber to select, by way of distinctive ringing, the particular person or extension that the subscriber wishes to alert.
  • *54 - Distinctive Ring C - Single Line Variety Package (SVP) : Allows a subscriber to select, by way of distinctive ringing, the particular person or extension that the subscriber wishes to alert.
  • *55 - Distinctive Ring D - Single Line Variety Package (SVP) : Allows a subscriber to select, by way of distinctive ringing, the particular person or extension that the subscriber wishes to alert.
  • *56 - Change Forward-To Number for ISDN Call Forwarding - Access code followed by directory number (DN) is used to change the Forward-To number for Call Forwarding Variable feature button. The state of Call Forwarding Variable feature button is not changed when this access code is utilized.
  • *57 - Customer Originated Trace - Provides the recipient of an abusive call the ability to request an auto-trace of the last call received.
  • *58 Activation, *59 Deactivation - ISDN MBKS Manual Exclusion - Access code allows a Multibutton Key Set (MBKS) user or an analog set user whose telephone number is shared on another ISDN MBKS to inhibit other stations from picking up a call on hold or bridging onto a call that is active at the station.
  • *60 Activation, *80 Deactivation - Selective Call Rejection - Allows the subscriber to have incoming calls from a limited number of calling parties rejected by the terminating switching system.
  • *61 Activation, *81 Deactivation - Distinctive Ringing/Call Waiting - Allows the subscriber to have incoming calls from a limited number of calling parties identified using distinctive alerting treatment.
  • *62 - Selective Call Waiting - Provides the subscriber the ability to provide a Call Waiting signal to a predetermined list of directory numbers specified by the subscriber. Callers not on the predetermined list will receive busy tone.
  • *63 Activation, *83 Deactivation - Selective Call Forwarding - Allows the subscriber to have incoming calls from a limited number of calling parties forwarded to a prespecified remote station.
  • *64 Activation, *84 Deactivation - Selective Call Acceptance - Provides the subscriber the ability to block calls from all but a predetermined list of directory numbers specified by the subscriber. Unaccepted callers may receive an announcement or be routed to a predetermined directory number.
  • *65 Activation, *85 Deactivation - Calling Number Delivery - Provides the subscriber with the directory number (DN) of the calling party during the ringing cycle.
  • *66 Activation, *86 Deactivation - Automatic Callback - Allows a subscriber to automatically place a call to the last station called by the subscriber when that station becomes idle.
  • *67 - Calling Number Delivery Blocking - Allows the subscriber to temporarily change the permanent public/private status indicator of his/her directory number (DN) and thus control its availability to the called party. Also known as per-phone call Caller ID Blocking
  • *68 Activation, *88 Deactivation - Call Forwarding Busy Line/Don't Answer - Allows a subscriber to forward calls intended for the subscriber's busy line, or idle line after a predetermined number of rings, to another directory number entered by the subscriber at the time of activation.
  • *69 Activation, *89 Deactivation - Automatic Recall - Allows a subscriber to hear the number of the last station that called the subscriber and automatically place a call, when that station becomes idle.
  • *70 - Cancel Call Waiting - Provides the subscriber the ability to disable the Call Waiting feature for the duration of a telephone call, such as during a short data transmission like a fax or modem call.
  • *71 - Usage Sensitive Three-way Calling - Allows a subscriber, by dialing an access code, to request the capability of adding a third party to the two-way connection that is established by subsequent dialing.
  • *72 Activation, *73 Deactivation - Call Forwarding - Allows a subscriber to redirect calls intended for his/her station (base station) to another station (remote station).
  • *74 Speed Calling 8-Change List, *75 Speed Calling 30-Change List - Speed Calling - Allows a subscriber to assign his/her own speed calling codes directly and immediately from his/her own telephone by dialing a change speed calling list access code, an abbreviated code, and a new telephone number.
  • *76 - Advanced Call Waiting Deluxe - Allows a subscriber to specify, in advance of incoming calls, the termination treatment on incoming calls that arrive while the subscriber is engaged in another conversation.
  • *77 Activation, *87 Deactivation - Anonymous Call Rejection - Allows Customers to reject calls from parties who have a privacy feature that prevents the delivery of their calling number to the called party. (Note to cell phone users: *77 on some cell phone networks in some locations is reserved for State Police, as it has the alphabetical equivalent of "*SP".)
  • *78 Activation, *79 Deactivation - Do Not Disturb - Provides the subscriber the opportunity of having all calls intercepted by the CO switch whenever the line is programmed for Do Not Disturb. The calling party will receive a message indicating the station is in Do Not Disturb condition.
  • *82 - Line Blocking Deactivation - Line Blocking Deactivation allows a caller to dial a delivery feature access code before dialing a complete telephone number to temporarily override the presentation status of both the caller's directory number and the calling name. If the caller enters the delivery code, then the calling identity presentation status will be shown as "public" for both caller directory number and calling name.
  • *90 Activation, *91 Deactivation - Customer Programmable Call Forwarding Busy Line - Allows subscriber of the feature to forward calls intended for the subscriber's busy line to another directory number entered by the subscriber at the time of activation. Deactivation will clear the forwarded-to directory number.
  • *92 Activation, *93 Deactivation - Customer Programmable Call Forwarding Don't Answer - Allows subscriber of the feature to forward calls intended for the subscriber's idle line, after a predetermined number of rings, to another directory number entered by the subscriber at the time of activation. Deactivation will clear the forwarded-to directory number.
  • *98 allows a user of voicemail to access it (in most Canadian Landlines, and VoIP services)
  • *99 allows a user of voicemail to access it (this is used by some independent telcos).
  • *123 allows a user of Vonage's voicemail to access it.
  • *228 - (also *ACT) Over-the-Air Service Provisioning - OTASP will enable the Service Provider to activate a potential service to a subscriber's wireless unit by downloading over the air required parameters, such as phone numbers, into the handset. Activation of the OTASP code, followed by supplemental digit strings, also provides the ability to securely load an Authentication Key into a subscribers wireless phone which is used to confirm and validate the identity of the wireless handset.
  • *272 - Wireless Priority Service - Access to Wireless Priority Service (WPS) - a nationwide cellular priority access capability in support of national security and emergency preparedness telecommunications.



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    Local Area Signalling Services (LASS) and Custom Calling Feature Control Codes:

    ServiceTonePulse/rotaryNotes
    Cancel forwarding30n/a[C1]
    Automatic Forwarding31n/a[C1]
    Notify32n/a[C1] [2]
    Intercom Ring 1 (..)511151[3]
    Intercom Ring 2 (.._)521152[3]
    Intercom Ring 3 (._.)531153[3]
    Extension Hold541154[3]
    Customer Originated Trace571157
    Selective Call Rejection601160(or Call Screen)
    Selective Distinct Alert611161
    Selective Call Acceptance621162
    Selective Call Forwarding631163
    ICLID Activation651165
    Call Return (outgoing)661166
    Number Display Blocking671167[4]
    Computer Access Restriction681168
    Call Return (incoming)691169
    Call Waiting disable701170[4]
    No Answer Call Transfer711171
    Usage Sensitive 3 way call711171
    Call Forwarding: start72 or 72#1172
    Call Forwarding: cancel73 or 73#1173
    Speed Calling (8 numbers)74 or 74#1174
    Speed Calling (30 numbers)75 or 75#1175
    Anonymous Call Rejection771177[5] [M: *58]
    Call Screen Disable801180(or Call Screen) [M: *50]
    Selective Distinct Disable811181[M: *51]
    Number Display Unblocking821182[4] [7]
    Select. Forwarding Disable831183[M: *53]
    ICLID[1] Disable851185
    Call Return (cancel out)861186[6] [M: *56]
    Anon. Call Reject (cancel)871187[5] [M: *68]
    Call Return (cancel in)891189[6] [M: *59]

    [edit] Notes

    [C1] - Means code used for Cellular One service
    [1] - for cellular in Pittsburgh, PA A/C 412 in some areas
    [2] - indicates that you are not local and maybe how to reach you
    [3] - found in Pac Bell territory; Intercom ring causes a distinctive ring to be generated on the current line; Hold keeps a call connected until another extension is picked up
    [4] - applied once before each call
    [5] - A.C.R. blocks calls from those who blocked Caller ID (used in C&P territory, for instance)
    [6] - cancels further return attempts
    [7] - *82 (1182) has been mandated to be the nationwide code for "Send CLID info regardless of the default setting on this phone line."
    [M: *xx] - alternate code used for MLVP (multi-line variety package) by Telcordia Technologies, (formerly Bellcore). It goes by different names in different RBOCs. In Bellsouth it is called Prestige. It is an arrangement of ESSEX like features for single or small multiple line groups. The reason for different codes for some features in MLVP is that call-pickup is *8 in MLVP so all *8x codes are reassigned *5x

  • Custom Local Area Signaling Services (CLASS) are PSTN telephony intelligent network services beyond basic voice calling, such as caller ID (automatic number identification (ANI)), caller number blocking, automated call return, call blocking or screening. Different IXCs offer various services. Late in the 20th century the term was simplified to LASS.
  • The services rely on the ITU-T standard Signalling System 7 (SS7) connectivity between network switches (SSPs) and databases (800 Database, LNPDB, LIDB, etc.) to operate. The CLASS standards were defined by Bellcore (now Telcordia Technologies) in the 1970s.
  • Some services such as call forwarding, three-way calling, call waiting, or speed dialing were sometimes condsidered part of custom calling rather than CLASS/LASS.
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