Ebooks are globally portable; including standardized international country codes ensures phone numbers remain functional regardless of the reader’s location.

Objectives

• Allow users to dial contact numbers immediately, regardless of their location or context of use.

Implementation

• Prefix every phone number with the two-digit international country code preceded by a plus sign (e.g., ‘+33’ for France). Replace the leading zero, often used in domestic dialing, with the country code.
• Format the phone number as a sequence of digit pairs separated by non-breaking spaces ( ). The first group must contain the plus sign and the country code, followed by a single digit for the area/network prefix to ensure consistent formatting (e.g., ‘+33 1 00 00 00 00’).

Control

• Identify all phone numbers in the content.
• Check that each number starts with a plus sign followed by a two-digit country code (e.g., ‘+33’).
• Verify that the leading zero (domestic prefix) has been removed and replaced by the country code.
• Ensure the number is formatted as a sequence of digit pairs separated by non-breaking spaces, where the first group is the country code and the second group contains a single digit (e.g., ‘+33 1 00 00 00 00’).