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What is E.164?

What is E.164

E.164 is an international phone numbering plan for public telecommunications.

This numbering format defines a general format for international phone numbers. It ensures that calls are delivered correctly by assigning a globally unique number to each device on the PSTN.

In this post, we will look at the E.164 format and components, along with examples.

E.164 Format

The proper E.164 format is [+] [country code] [area code] [subscriber number].

This number can have a maximum of 15 digits. And there should be no brackets or parentheses when using these numbers.

E.164 Example

You might have seen US phone numbers written as +13051234567 or UK phone numbers as +442045678910. These are examples of proper E.164 formatting.

An example of proper E.164 formatting.

It’s essential to use this formatting when dialing international phone numbers because E.164 is an international standard that carriers use to route calls.

E.164 Formatting Components

E.164 formatting consists of the following components:

  • Plus sign (+)
  • Country calling code
  • National destination or area code
  • Subscriber number.

There are an estimated 100 trillion permutations with this global numbering format.

How to Work with E.164 Formatted Numbers

If one doesn’t follow the proper format, carriers won’t be able to determine the destination of your call, and the call might not be completed.

Luckily, some calling tools automatically convert phone numbers to E.164 format using Javascript.

Benefits of These Numbers

This global numbering standard has many benefits for international communications:

  • Internationally recognized global standard
  • Defines telephone number formats
  • Helps secure the deliverability of calls
  • Ensures that each device has a unique phone number
  • Compatible with legacy technologies
  • Designed to support future growth.

Most importantly, these numbers ensure that you can reach any device on the PSTN and that calls are delivered properly.

E.164 Categories and Types

A) Categories

This numbering format is broken down into five categories of phone numbers used in global public telecommunications:

  1. Geographic areas
  2. Global services
  3. Networks
  4. Groups of countries
  5. Trials

For each category, the ITU details the components of the number structure and the digit analysis needed to successfully terminate the calls. For example, numbers in the trial category have fewer digits than phone numbers for geographic areas.

B) Types

Recommendations to E.164 have been issued several times, with each recommendation intended to ensure better functionality.

  • E.164.1

This recommendation – issued in 2005 – encourages the efficient use of available number resources.

  • E.164.2

This recommendation created the fifth category of E.164. It details the requirements for granting three-digit identification codes to organizations conducting global non-commercial trials.

  • E.164.3

This recommendation determines the procedures for the assignment and reclamation of E.164 country codes and associated ID codes for groups of countries.

Brief History and Where It’s Going

E.164 was developed by the International Telecommunications Union (ITU).

Rapid advances in telecommunication technology created a need to provide uniform access to various network structures.

Originally called the Numbering Plan for the ISDN Era, this plan has undergone several revisions. The current version is the successor to E.163.

Plans are underway to expand E.164. The expansion will likely be a protocol called Telephone Number Mapping or ENUM.

This protocol will assign a unique uniform resource identifier (URI) to all internet-connected devices worldwide, including legacy devices. It will further enable all network devices to communicate with each other using a network address or unique phone number.

How Global Call Forwarding Can Help

Our telecom experts are prepared to help with your E.164 issues. We can provide consultations and solutions to help you dial international phone numbers correctly. We can also help you follow proper formatting for the international virtual phone numbers that you purchase from us.

Call us at +1 (561) 908-6171 and talk to a global telecommunications expert.

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