10-digit dialing
Encyclopedia
In the United States
and Canada
, 10-digit dialing is a popular term used to refer to the practice of including the area code of a phone number when dialing. Sometimes (see below), an initial "1" is used; such dialing is known as 11-digit dialing or national format.
.
In this case, it is only necessary to dial the area code for a domestic call when the area code of the called number was different from that of the calling number. The phone system requires the caller to dial a "1" before the area code and number, to indicate to the phone system that the call will require a connection to another area, as trunk prefix
. ("1" is also the country code
for the North American Numbering Plan including United States and Canada, and therefore must likewise be dialed before the area code for international calls made to these countries.) Typically such calls were long distance call
s. It used to be that a call to a different area code was by definition a long-distance call, but the significant growth in the number of area codes (and the shrinking of the areas they occupy) since that time has invalidated this assumption.
In Canada and some regions of the United states, dialing a "1" before an area code where the outgoing call is in the same service area results in an automated recording indicating that the call being made is local and a "1" is not necessary, even if the area codes are different. This is common in areas where overlays are being used. Phone companies have also warned that dialing "1" when it is unnecessary could result in long distance charges being made even when they otherwise would not have been charged.
s as a means to reduce the need for phone numbers to change as a result of adding new area codes meant that one geographic area could be associated with more than one area code. This is disadvantageous to new service providers as existing providers can issue numbers in the familiar area code. In order to promote fairness among carriers, 10-digit dialing became an FCC requirement; though the "1" before the area code is often required only for actual long distance calls. Some phone systems in early overlay plan areas still do not accept a "1" before the area code for non-long-distance calls.
The added dialing requirement, coupled with the need to remember which of the area's concurrent area codes applied to a given number, damaged the popularity of overlay plan
s, which themselves were introduced as a means to reduce the inconveniences associated with the traditional split plan
s.
As overlay plans have spread to more areas, 10-digit dialing in the U.S. and Canada is becoming increasingly common. However, areas not within an overlay plan can still use 7-digit dialing for local calls, although local long distance calls may require 10-digit dialing even within the same area code.
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
and Canada
Canada
Canada is a North American country consisting of ten provinces and three territories. Located in the northern part of the continent, it extends from the Atlantic Ocean in the east to the Pacific Ocean in the west, and northward into the Arctic Ocean...
, 10-digit dialing is a popular term used to refer to the practice of including the area code of a phone number when dialing. Sometimes (see below), an initial "1" is used; such dialing is known as 11-digit dialing or national format.
"Standard" dialing
Traditionally, after the advent of area codes, the phone system allows callers to dial only the local portion of the phone number they wanted to reach, as long as the called number was in the same area code as that of the caller. For example, a person whose full national phone number was 212-555-7890 was able to call a number located at 212-555-3456 by simply dialing 555-3456. The phone system infers that the desired number was in the same area code, and connects the call accordingly. This is now known retrospectively as 7-digit dialing7-digit dialing
7-digit dialing is a popular term referring to the traditional convention in the United States and Canada for dialing local phone calls. It is also sometimes known as local format or network format....
.
In this case, it is only necessary to dial the area code for a domestic call when the area code of the called number was different from that of the calling number. The phone system requires the caller to dial a "1" before the area code and number, to indicate to the phone system that the call will require a connection to another area, as trunk prefix
Trunk prefix
A trunk prefix is the number to be dialed in a domestic telephone call, preceding any necessary area codes and subscriber numbers. When the number is called from overseas, the trunk prefix is omitted by the caller. In most countries, such as Australia, Germany and the United Kingdom, the trunk...
. ("1" is also the country code
E.164
E.164 is an ITU-T recommendation that defines the international public telecommunication numbering plan used in the PSTN and some other data networks. It also defines the format of telephone numbers. E.164 numbers can have a maximum of fifteen digits and are usually written with a + prefix...
for the North American Numbering Plan including United States and Canada, and therefore must likewise be dialed before the area code for international calls made to these countries.) Typically such calls were long distance call
Long Distance Call
"Long Distance Call" is an episode of the American television anthology series The Twilight Zone.-Synopsis:A boy communicates with his father's European-immigrant mother, who had recently died, using a toy telephone that she gave him on his birthday before her passing. The boy, Billy, runs out in...
s. It used to be that a call to a different area code was by definition a long-distance call, but the significant growth in the number of area codes (and the shrinking of the areas they occupy) since that time has invalidated this assumption.
In Canada and some regions of the United states, dialing a "1" before an area code where the outgoing call is in the same service area results in an automated recording indicating that the call being made is local and a "1" is not necessary, even if the area codes are different. This is common in areas where overlays are being used. Phone companies have also warned that dialing "1" when it is unnecessary could result in long distance charges being made even when they otherwise would not have been charged.
Overlay plans
The introduction of overlay planOverlay plan
In telephony, especially in North America, an overlay plan is the practice of introducing a new area code by applying it onto a geographic area that is already occupied by one or more existing area codes, resulting in two area codes serving the same area.- Methodology :Prior to the introduction of...
s as a means to reduce the need for phone numbers to change as a result of adding new area codes meant that one geographic area could be associated with more than one area code. This is disadvantageous to new service providers as existing providers can issue numbers in the familiar area code. In order to promote fairness among carriers, 10-digit dialing became an FCC requirement; though the "1" before the area code is often required only for actual long distance calls. Some phone systems in early overlay plan areas still do not accept a "1" before the area code for non-long-distance calls.
The added dialing requirement, coupled with the need to remember which of the area's concurrent area codes applied to a given number, damaged the popularity of overlay plan
Overlay plan
In telephony, especially in North America, an overlay plan is the practice of introducing a new area code by applying it onto a geographic area that is already occupied by one or more existing area codes, resulting in two area codes serving the same area.- Methodology :Prior to the introduction of...
s, which themselves were introduced as a means to reduce the inconveniences associated with the traditional split plan
Split plan
In telephony, a split plan is the practice of introducing a new area code by dividing an existing area code's territory and applying the new area code to one of the resulting divisions, replacing the existing area code within that section....
s.
As overlay plans have spread to more areas, 10-digit dialing in the U.S. and Canada is becoming increasingly common. However, areas not within an overlay plan can still use 7-digit dialing for local calls, although local long distance calls may require 10-digit dialing even within the same area code.
As a number format
As the familiarity of overlay plans and 10-digit-dialing required areas has increased, the phrase "10-digit dialing" is now sometimes used to describe the normal inclusion of area code in long-distance dialing.See also
- List of country calling codes
- North American Numbering PlanNorth American Numbering PlanThe 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...
- Telephone numbering planTelephone numbering planA telephone numbering plan is a type of numbering scheme used in telecommunications to allocate telephone numbers to subscribers and to route telephone calls in a telephone network. A closed numbering plan, such as found in North America, imposes a fixed total length to numbers...