User IDs
When adding a user from the Maintain Users page, the Enter User ID dialog box is displayed. Each user must have a unique user ID. If you enter a user ID that has already been assigned to another user, even a user whose account has been disabled, a warning is displayed and you must enter a different user ID.
User IDs can contain the following items:
•  Both uppercase or lowercase letters and numbers (e.g., Mike1)
•  Periods, dashes, underscores, or parentheses (e.g., jim.smith, jim_smith)
•  Up to 30 characters
The word ALL cannot be included in the user ID, regardless of case.
When you have entered an appropriate code word, click Continue (ALT+C), and complete the user record fields.