AT&T MERLIN LEGEND Release 3.1 System Manager's Manual page 158

Features
Night Service Exclusion List and/or Emergency List. Allow some calls
when Night Service with the Outward Restriction option is used.
Pool Dial-Out Code Restriction (Hybrid/PBX Only). Restrict specific
pools. This can be used to reserve certain pools for specific purposes,
for example, for data communications.
Facility Restriction Levels (Hybrid/PBX Only). Automatic Route
Selection (ARS) allows Facility Restriction Levels (FRLs) to be applied to
both outside trunks and extensions for the most reliable control of toll
calling.
IMPORTANT:
1. In Release 3.1 and later systems, a system programming feature allows you
to help guard against toll fraud when star codes are dialed under certain
circumstances. Star codes, typically dialed before an outgoing call, provide
special services from the CO. For example, in many areas a telephone user
can dial
caller identification at the receiving party's telephone (to allow or disallow star
codes preceding a call, see Chapter 6, "Managing the System"). Some
central offices supply a second dial tone following the dialed star (*) code, to
signal customers that they must dial additional digits. If this second dial tone
is not immediate, a hacker can enter digits that are not detected by the CO
but are detected by the system's calling restrictions. If your business uses
central office star codes and the CO issues a second dial tone after a pause,
see System Programming for information about including a timed delay that
will cause the system to prevent the call when digits are entered during the
pause.
2. In Behind Switch mode, calling restrictions must be supplied by the host
system, not by the MERLIN LEGEND Communications System.
3. In Release 3.1 and later systems, the system provides certain default calling
restrictions that make it easier for system managers to guard against toll
fraud. These are described below with the specific features they affect.
This section describes each of these features. Some of these features are
combined with security measures to prevent system abuse by remote access
users or hackers. In addition, users can be assigned authorization codes, which
they can enter when they are away from their extensions. When a person enters
an authorization code while visiting another system extension, the calling
restrictions assigned to his or her own extension are applied to the call. For
more information, see "Authorization Codes," later in this section.
!
SECURITY ALERT:
For more information see the section, "Security," later in this chapter. Also
consult "Security of Your System: Preventing Toll Fraud," in Appendix A,
"Customer Support Information."
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Features and Applications
before a telephone number to disable central office-supplied