Apple Remote Access MultiPort Server - Manual (Page 36)

9 If you want to require callbacks, click the Call Back at # checkbox and type in the
callback number.
The callback number is the telephone number provided to you by a user for
remote access. Selecting this option means that when the user calls the server,
the server computer will temporarily disconnect the user, then immediately
call the user at the number you’ve entered. The callback feature is optional; it
provides an extra level of security, because the user must call from a specific
phone number.
You enter the phone number as if you were dialing directly. Type in any dialing
prefixes, such as “1” for long-distance calling in the United States and an area
code. If the server needs to dial an outside line (as in many business phone
systems), type the outside line number, followed by a comma. For example,
type 9, 1-415-555-1234. The comma in this example indicates a pause during
dialing so that the modem can connect to an outside telephone line from a PBX.
The hyphens are included for readability but are not required.
Note: If you deselect the callback option, the phone number is saved, but
is unused.
36 Chapter 3 / Setting Up the Server