Importance of E.164 format

All kinds of telephony services are now available around the globe, through technology, one part of the world can easily reach the other part via just a phone call, SMS/MMS and fax. Although this sort of flexibility brings the entire world together, it also opens doors to ambiguities and confusions.

A phone number can have up to 15 digits out of which the first part is represented by the Country Code (CC) that may range between one to three digits. This is represented by E.164 format. It is an internationally accepted format to uniquely identify each phone number used for services that allow international communication in order to avoid any sort of incorrect interpretation.

For instance, an Indian number from a particular region may have a state code of 044 and the phone number may begin with something like 440123XXXX. If an international country code is not added, there may be an ambiguity caused by the system making an attempt to interpret the number incorrectly, since +44 is the country code of United Kingdom, the number could also be +440123XXXX, that is, a UK number. Hence a +91 must be added before the number 440123XXXX to identify it as an Indian number.

This is the reason why E.164 is highly recommended by RingCentral in order to avoid such ambiguities. Several SDKs provided by RingCentral require that the phone numbers be entered along with the International country code. Not ensuring this, could be one of reasons you might encounter an exception such as “Invalid resource owner credentials”.

The international country codes for all countries can be found here. Once you have your country code, make sure to prefix it to the number keeping in mind that the first 0 should be removed and the special characters, that make up a phone number, such as, the parenthesis({ }) and dashes(-) must be removed. Lastly, ensure that the plus (+) sign at the very beginning of the phone number, isn’t forgotten.