Call forwarding
Encyclopedia
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 invented by Ernest J. Bonanno. In North America, the forwarded line usually (though not always) rings once to remind the customer using Call forwarding that the call is being redirected. More consistently, the forwarded line indicates its condition by stutter dial tone.
In Europe, most networks indicate that unconditional call forwarding is active with a special dial tone
. When the phone is picked up it is immediately apparent that calls are being forwarded.
In common language, the terms "Call forwarding" and "Call diversion" are both used to refer to any feature that allows a call to be routed to a third party, and the terms are generally interchangeable.
, the NANP generally uses the following vertical service code
s to control call forwarding:
The Sprint Nextel
cellphone company uses these:
Most EU fixed-line carriers use the following codes based on CEPT
and ETSI
standards developed in the 1970s on both POTS
and ISDN lines: (There may be some variation to these, but the unconditional code *21*, is very much universally standard on EU telephone lines.) The general syntax for all European service codes always follows the pattern below:
For GSM/3GSM (UMTS) phones, the GSM
standard defines the following forwarding codes
. These were developed by ETSI and are based on standard European diversion codes and are similar to those used on most landlines in the EU:
If the prefix to the forwarding command is "**" (instead of the usual "*"), then the phone number in that command is registered in the network. If after that the forwarding is deactivated using a command with a single "#", then later it will be possible to re-activate this forwarding again with a simple "*" command without a phone number in it. The forwarding will be re-activated to the number registered in the network. For example, if one uses the out-of-reach code in a forwarding command:
and after that one deactivates the forwarding:
then later it will be possible to re-activate the out-of-reach forwarding without specifying a number:
After the above command, all calls made to the phone, while it is out of reach, will be forwarded to 7035551212. It is possible to activate the feature to a number other than the registered number, whilst still retaining the registered number for later use. For example, issuing the command:
will result in calls being forwarded to 7185551212 (and not to the registered number 7035551212). However, if later a command is issued:
then the calls will again be forwarded to the registered number 7035551212 (and not to the number from the previous forwarding command 7185551212).
Additionally, in GSM networks, such as T-Mobile and AT&T Mobility in USA, and all mobile networks in EU, it is possible to set the number of seconds the phone will ring before forwarding. This is specified by inserting "*SC*XX" prior to the final "#" of the forwarding command, where "SC" is a service type code (11 for voice, 25 for data, 13 for fax), and "XX" is the number of seconds in increments of 5 seconds. If "SC" is omitted (just "**XX") then by default all service types will be forwarded. For example, forwarding on no-answer can be set with:
In some networks there may be a limit of not more than 30 seconds before forwarding (i.e. "XX" can only be 5, 10, 15, 20, 25 or 30; all greater values, like 45 and 60, will result in the forwarding command being rejected and an error message returned).
Some businesses find that the human touch can improve contact, thus sales, but traditional wired answering services are expensive, so they have their calls forwarded to a call center, so the client can reach an operator instead of an answering machine or voice mail.
Some services offer international call forwarding by allocating for the customer a local virtual phone number which is forwarded to any other international destination.
How To Forward Your Calls on cell phone
Telephony
In telecommunications, telephony encompasses the general use of equipment to provide communication over distances, specifically by connecting telephones to each other....
, is a feature on some telephone networks allowing an incoming call to a called party
Called party
The called party is a person who answers a telephone call. The person who initiates a telephone call is the calling party....
to be redirected to a third party. For example, the third party may be a mobile telephone, voicemail box or other telephone number
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...
where the desired called party is situated. It was invented by Ernest J. Bonanno. In North America, the forwarded line usually (though not always) rings once to remind the customer using Call forwarding that the call is being redirected. More consistently, the forwarded line indicates its condition by stutter dial tone.
In Europe, most networks indicate that unconditional call forwarding is active with a special dial tone
Dial tone
A dial tone is a telephony signal used to indicate that the telephone exchange is working, has recognized an off-hook, and is ready to accept a call. The tone stops when the first numeral is dialed...
. When the phone is picked up it is immediately apparent that calls are being forwarded.
Terminology
The ISDN Diversion supplementary services standards document uses "diversion" as a general term to encompass specific features including "Call Forwarding Busy", "Call Forwarding No Reply" and "Call Deflection".In common language, the terms "Call forwarding" and "Call diversion" are both used to refer to any feature that allows a call to be routed to a third party, and the terms are generally interchangeable.
Keypad codes
Special types of call forwarding can be activated only if the line is busy, or if there is no answer, or even only for calls from selected numbers. In North AmericaNorth America
North America is a continent wholly within the Northern Hemisphere and almost wholly within the Western Hemisphere. It is also considered a northern subcontinent of the Americas...
, the NANP generally uses the following vertical service code
Vertical service code
A vertical service code or VSC is a special code dialed prior to a telephone number that engages some type of special telephone service...
s to control call forwarding:
| Forward service | Activation | Deactivation | Number change |
|---|---|---|---|
| All calls | *72 and 10 digits local phone number (some larger cities require *72 and 1 and 10 digits) | *73 | |
| On busy or no answer | *68 | *88 | |
| From select callers | *63 | *83 | |
| On ISDN | *56 | ||
| Customer-programmable features (where available): | |||
| Busy line | *90 | *91 | *40 |
| No answer | *92 | *93 | *42 |
The Sprint Nextel
Sprint Nextel
Sprint Nextel Corporation is an American telecommunications company based in Overland Park, Kansas. The company owns and operates Sprint, the third largest wireless telecommunications network in the United States, with 53.4 million customers, behind Verizon Wireless and AT&T Mobility...
cellphone company uses these:
| Forward service | Activation | Deactivation |
|---|---|---|
| On busy or no answer | *28[phone number] | *38 |
| On busy | *74[phone number] | *740 |
| On no answer | *73[phone number] | *730 |
| Immediately | *72[phone number] | *720 |
- All call forwarding is included at no additional cost for customers on the Simply Everything Plan. For other service plans, calls forwarded immediately (Unconditional Call Forwarding, *72) costs $0.20/min. Forwarding calls to another number if the person who's calling you gets no answer or a busy signal is free. This is called Conditional Forwarding (*73, *74 or *28).
- Some carriers (including Verizon Wireless) use *71 for conditional forwarding although this is not standard.
- Sometimes, to deactivate a call forwarding, *720 will work on cellphones.
Most EU fixed-line carriers use the following codes based on CEPT
European Conference of Postal and Telecommunications Administrations
The European Conference of Postal and Telecommunications Administrations was established on June 26, 1959, as a coordinating body for European state telecommunications and postal organizations...
and ETSI
European Telecommunications Standards Institute
The European Telecommunications Standards Institute is an independent, non-profit, standardization organization in the telecommunications industry in Europe, with worldwide projection...
standards developed in the 1970s on both POTS
Plain old telephone service
Plain old telephone service is the voice-grade telephone service that remains the basic form of residential and small business service connection to the telephone network in many parts of the world....
and ISDN lines: (There may be some variation to these, but the unconditional code *21*, is very much universally standard on EU telephone lines.) The general syntax for all European service codes always follows the pattern below:
| Forward service | |Cancel & Deregister | |Status | Unconditional forwarding: | ||
|---|---|---|---|---|---|
| all calls (unconditionally) | *21*[phone number]# | #21# | #21# | *#21# | *21# |
| Conditional forwarding: | |||||
| if busy | *69*[phone number]# or *67*[phone number]# | #69# or #67# | #69# or #67# | *#69# or *#67# | *69# or *67# |
| if not answered | *61*[phone number]# | #61# | #61# | *#61# | *61# |
For GSM/3GSM (UMTS) phones, the GSM
Global System for Mobile Communications
GSM , is a standard set developed by the European Telecommunications Standards Institute to describe technologies for second generation digital cellular networks...
standard defines the following forwarding 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...
. These were developed by ETSI and are based on standard European diversion codes and are similar to those used on most landlines in the EU:
| Forward service | |Cancel & Deregister | |Status | Unconditional forwarding: | ||
|---|---|---|---|---|---|
| all calls | *21*[phone number]# | ##21# | #21# | *#21# | *21# |
| Conditional forwarding: | |||||
| if busy | *67*[phone number]# | ##67# | #67# | *#67# | *67# |
| if not answered | *61*[phone number]# | ##61# | #61# | *#61# | *61# |
| if out of reach | *62*[phone number]# | ##62# | #62# | *#62# | *62# |
| all forwards | *002*[phone number]# | ##002# | #002# | *#002# | *002# |
| all conditional forwards | *004*[phone number]# | ##004# | #004# | *#004# | *004# |
If the prefix to the forwarding command is "**" (instead of the usual "*"), then the phone number in that command is registered in the network. If after that the forwarding is deactivated using a command with a single "#", then later it will be possible to re-activate this forwarding again with a simple "*" command without a phone number in it. The forwarding will be re-activated to the number registered in the network. For example, if one uses the out-of-reach code in a forwarding command:
**62*7035551212#and after that one deactivates the forwarding:
#62#then later it will be possible to re-activate the out-of-reach forwarding without specifying a number:
*62#After the above command, all calls made to the phone, while it is out of reach, will be forwarded to 7035551212. It is possible to activate the feature to a number other than the registered number, whilst still retaining the registered number for later use. For example, issuing the command:
*62*7185551212#will result in calls being forwarded to 7185551212 (and not to the registered number 7035551212). However, if later a command is issued:
*62#then the calls will again be forwarded to the registered number 7035551212 (and not to the number from the previous forwarding command 7185551212).
Additionally, in GSM networks, such as T-Mobile and AT&T Mobility in USA, and all mobile networks in EU, it is possible to set the number of seconds the phone will ring before forwarding. This is specified by inserting "*SC*XX" prior to the final "#" of the forwarding command, where "SC" is a service type code (11 for voice, 25 for data, 13 for fax), and "XX" is the number of seconds in increments of 5 seconds. If "SC" is omitted (just "**XX") then by default all service types will be forwarded. For example, forwarding on no-answer can be set with:
*61*[phone number]**[seconds]#In some networks there may be a limit of not more than 30 seconds before forwarding (i.e. "XX" can only be 5, 10, 15, 20, 25 or 30; all greater values, like 45 and 60, will result in the forwarding command being rejected and an error message returned).
When and Why to Use it
Diverting calls can increase one's availability to a caller. The main alternative is an answering machine or voicemail, but some callers do not wish to leave a recorded message, suspecting that the party will delay returning their messages.Some businesses find that the human touch can improve contact, thus sales, but traditional wired answering services are expensive, so they have their calls forwarded to a call center, so the client can reach an operator instead of an answering machine or voice mail.
Some services offer international call forwarding by allocating for the customer a local virtual phone number which is forwarded to any other international destination.
External links
- Call Forwarding User manual, Bell Canada
How To Forward Your Calls on cell phone