ZyXEL Communications 2864I - Manual (Page 81)

68 Dial-In Configuration
Once you have completed filling in Menu 14.1 - Edit Dial-in User ,
press ENTER at the message: Press ENTER to Confirm ... to save
your selections, or press ESC at any time to cancel your selections.
More on CLID
CLID allows the Prestige to authenticate the caller before a call is
answered, thus saving the cost of a connection. The Prestige uses
the caller ID in the ISDN call setup message to match against the
CLID in the database.
However, CLID may not be available due to your switch
configuration.
Besides authentication, another application of CLID is to combine
it with call back. For instance, your company pays for the
connection charges for telecommuting employees, and you are
using the Prestige as the dial in server. You can turn on both the
CLID authentication and call back options for the dial-in users. By
doing so, all usage are charged to the company instead of the
employees, and your accounting department can avoid the hassles
of accountability and reimbursement.