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MERLIN LEGEND Communications System Release 5.0
System Manager’s Guide
555-650-118
Issue 1
June 1997
Features and Applications
Page 4-41Features
4
special services from the CO. For example, in many areas a telephone user can
dial
*67
before a telephone number to disable central office-supplied caller
identification at the receiving party’s telephone. (To allow or disallow star codes
preceding a call, see ‘‘
Revising Allowed Lists’’ on page 6-69 or ‘‘Revising
Disallowed Lists’’ on page 6-72.)
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 causes the
system to prevent the call when digits are entered during the pause.
In Behind Switch mode, calling restrictions must be supplied by the host system,
not by the MERLIN LEGEND Communications System.
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 type of calling restriction. 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’’ on page 4-46.
SECURITYlALERT:
!
For more information see the section, ‘‘Security’’ on page 4-47. Also consult
‘‘
Security of Your System: Preventing Toll Fraud’’, in Appendix A,
‘‘Customer Support Information’’.
When you change your system, be aware of the following special considerations
that apply to toll calling:
■ The Remote Access feature allows employees to dial into the system by
dialing the number of a trunk designated for remote access. After a remote
access caller reaches the system, you should make sure that he or she
must dial a password (called a
barrier code
). After gaining access to the
system, the user can, among other things, select a regular or
special-purpose outside line (for example, a WATS line) or a pool or an
ARS line to make outgoing calls. You can apply calling restrictions to
outside lines used to access the system remotely; you can also apply
restrictions to barrier codes just as though they were system extensions.