E.164 international standard

This article explores the E.164 international telephone numbering plan, which ensures that every device on the Public Switched Telephone Network (PSTN) possesses a globally unique number. This standardized system is essential for routing phone calls and text messages accurately to individual devices across different countries. In accordance with the official ITU E.164 recommendation, the format must consist of a plus sign [+], a [country code], and a [subscriber number including area code], with a total length not exceeding fifteen digits.