A telephone prefix is the first set of digits after the country, and area codes of a telephone number; in the North American Numbering Plan countries (country code +# ), it is the first three digits of a seven-digit phone number, 3-3-4 scheme. In other countries both the prefix and the number may have different lengths. It shows which exchange the remaining numbers refer to. A full telephone number is usually made up of country code (required for international calls only), area code (required for calls between telephone areas), prefix, and subscriber number.
Some places restrict certain prefixes to fax numbers or cell phones only; in other places such dedicated prefixes are not used.
As telephone technology advanced, the precise significance of the prefix became blurred in many places; # 485 in London, UK, was once the GULliver exchange, but now 44-20-7485-xxxx is just considered one of many number blocks served by the CLKEN Kentish Town exchange; 44-20-770703xx is another.
Where the digits in my phone number come from?
Did you ever wonder where the digits in your phone number come from, and what they mean? As you probably suspected, each segment has a reason for being there.
Like most codes, it contains information in each part that allows it to function properly and to send your call to the right place. If you dial a phone number using even one digit more or less than the exact code (we’ve all tried it), then you quickly find that it simply doesn’t work.
While we take it for granted that phone numbers work and don’t really think about how this number connects our call, the system is made possible by those groups of numbers working together in just the right way.
First things first—let’s name each part of a phone number, and then we’ll get into their respective functions.
The first grouping is of course, the area code. The area code is the identifier for a geographic region.
The next grouping is the 3-digit prefix, which narrows the location of the phone number a little further.
Finally, there is the line number. These are the last 4 digits of the phone number which directs a call to a specific phone line.
What are area codes?
Area codes bring a call to the larger geographic region which may contain multiple towns; at the same time, large cities generally have multiple area codes.
There are two basic types of area codes: Local and Toll Free. Toll free area codes are 800, 844, 855, 866, 877, and 888; local area codes are all the other ones.
Then of course, there is the 900 area code which represents a “toll” number, or “pay-per-call”, which many of us remember as the rather conspicuous area code.
After the area code, you have the prefix. The prefix expectedly provides a more narrowed location of a telephone number, signifying a specific location such as a town.
The area code generally does not need to be dialed when calling another number with the same prefix.