E.164 number format

E.164 is the international standard for phone number formatting, ensuring numbers are globally unique and unambiguous. CM.com requires all numbers for outbound calling to be formatted using E.164, where the initial + sign is optional.

Structure

+[country code][subscriber number]

Rules

• Starts with a + sign

• Followed by the country code (1–3 digits)

• Followed by the national subscriber number

• Maximum total length: 15 digits (excluding the +)

• No spaces, dashes, parentheses, or other formatting characters

Examples