Hello Jeff,
Are you referring to ‘Phone and modem options dialog (a Windows control panel dialog)’ or the ‘Check Number dialog in Outlook’?
If you’re referring to the ‘Check number dialog in Outlook’ which would allow you to enter Country region and area codes, then Once you enter phone number to the field, double click on it and see if you get the window of
‘Check phone numbers’.
Once you have the ‘Check phone numbers’ dialog open, enter the required information.
For further clarifications, reply and we would be happy to assist.
Thank you.