E.164 Phone Standard Communicates Standard with VoIP Phone and PSTN Phone

E.164 Phone Standard Communicates Standard with VoIP Phone and PSTN Phone.

E.164 is an ITU-T recommendation, titled The international public telecommunication numbering plan, that defines a numbering plan for the world-wide public switched telephone network (PSTN) and some other data networks. E.164 defines a general format for international telephone numbers.
 
VoIP phone comes with the e164 telecom standards which allows you to communicate over the e164 telecom standard network.  E164 is the defacto telecom standard when it comes to telecom and voice over IP phones alike.  E164 is activated in the backend of the programming code so that you never miss a beat with VoIP phone or E164 standards.

This recommendation provides the number structure and functionality for the three categories of telephone numbers used for international public telecommunication:

For each of the categories, it details the components of the numbering structure and the digit analysis required to successfully route the calls. Annex A provides additional information on the structure and function of E.164 numbers. Annex B provides information on network identification, service parameters, calling/connected line identity, dialing procedures, and addressing for Geographic-based ISDN calls. Specific E.164-based applications which differ in usage are defined in separate recommendations.

The number categories are all based on a fifteen-digit numbering space. Before 1997, only twelve digits were allowed. The definition does not include any international call prefixes, necessary for a call to reach international circuits from inside the country of call origination.

All VoIP phones with Skybridge Domains, Get Phone and Next Call Telecom allows you to call using e164 standards.

Read on the wiki e164 telecom standard