The Difference Between Open And Closed Dialing Systems
An open dialing plan occurs when long distance phone calls and local phone calls require different arrangements. Therefore, if you are calling a number within the same city, only the number must be dialed. However, in the case where calls must be made outside the city, an area code must be dialed. When calling from outside the area, a trunk code is required. The trunk code usually begins with the number “0”. The trunk code is not used when calling from outside the country, as it is replaced by the country code.
The United States and Canada, as well as the other countries participating in NANP use the trunk code “1”, which is also the country code.
It should be noted that open and closed dialing plans are not the same as open and closed numbering plans, as numbering plans which are found in North America, are fixed-length area codes and local numbers. An open numbering plan, found in other countries which have not yet standardized, experience varying lengths of area codes and/or local numbers.
Closed Dialing Plans
Closed dialing plans are much more rare. They occur when a subscriber’s number is a standard length, and where it is used for all calls, even within the same area. This is typically the case in countries that do not have area codes because they are not required. However, more recently, many countries are working to standardize the length of their phone numbers and area codes, and are working the area code into the telephone number of the customer. This usually makes trunk codes obsolete.
Though it isn’t as user-friendly or convenient to use full national dialing even when making a local call, it makes the quantity of available numbers much more realistic considering the increase in mobile phones, pagers, and dedicated fax and internet lines.
Travis Craig writes informative articles about phone numbers, area codes, and how to find out more information about them. Find more information 203 phone numbers at http://www.203phonenumbers.com
Tags: area codes, cell phone number, exchanges, nanpa, npa, nxx, phone, phone numbers, prefix, telephone
