AT&T MERLIN LEGEND System Reference Manual page 364

Features
Considerations
Allowed List Assignment. Used
from making local and/or toll calls. Up to eight Allowed Lists enable restricted
Remote Access users to call specific numbers (local or toll). When barrier
codes are not used, Allowed Lists are assigned to all lines/trunks and cannot
be assigned to individual lines/trunks. When barrier codes are used, Allowed
Lists are assigned to individual barrier codes.
Disallowed List Assignment. Used when a Remote Access user is not
restricted from making calls. A Disallowed List is assigned to prevent the
user from dialing specific numbers on the list. When barrier codes are not
used, Disallowed Lists are assigned to all line/trunks and cannot be
assigned to individual lines/trunks. When barrier codes are used, Disallowed
Lists are assigned to individual barrier codes.
Automatic Callback. The factory setting prevents a remote caller who
reaches a busy trunk pool (Hybrid/PBX only) or extension from using the
automatic Callback feature to request a trunk pool or extension. The factory
setting can be changed to allow remote users to use automatic Callback to
request busy trunk pools or extensions. Automatic Callback assignment
applies to all Remote Access users and cannot be assigned to lines/trunks or
barrier codes on an individual basis.
Up to 16 four-digit barrier codes can be programmed, each with its own
restriction.
Under applicable tariffs, the customer is responsible for any charges
incurred through the remote use of system facilities. To prevent unauthorized
use of the system's outside lines by remote callers, also called "toll fraud," the
following precautions should be taken:
Barrier codes should be changed frequently.
The lines and/or trunks to which remote access is assigned should be
changed frequently.
See "Security of Your System-Preventing Toll Fraud" at the front of this book
for more detailed instructions on preventing toll fraud.
Only touch-tone telephone users can access the system remotely. Rotary
dial telephone users are routed through the system operator.
Remote Access calls ring on Intercom or System Access buttons; however,
the telephone rings like an outside incoming call.
Systems with DID trunks can designate a DID extension that off-site users
can dial to use Remote Access.
If a remote caller does not dial a number or feature code before the timeout
period expires, the call is sent to a system operator or other designated
telephone.
Remote Access users are restricted
when
Remote Access 2-315