Ensure phone numbers meet the ITU E.123 standard
The International Telecommunication Union (ITU) publishes a recommendation entitled “Notation for National and International Telephone Numbers, E-mail Addresses and Web Addresses.” Recommendation E.123 specifies the format of telephone numbers assigned to telephones and similar communication endpoints in national telephone numbering plans.
Why is this important for the phone numbers in your Active Directory? You may have applications that read user’s phone numbers from the Active Directory such as Teams, SharePoint, Outlook signature generators, and web-applications to present click-to-dial feature. If these phone numbers are not correct, click-to-dial applications will not work.
Both Ithicos’ Directory Update and Directory Manager user editing features allow the system administrator to define a phone number format standard for each type of phone number attribute on the editing screen. When a user types a phone number with the incorrect format, they are presented with a message with a customizable help message.
Once a phone number is saved to your on-premises Active Directory, it should replicate to Microsoft Entra ID if you are replicating your local directory to Microsoft 365.
Last Review: 5 Sept 2024