AT&T MERLIN LEGEND Release 3.1 System Planning Manual page 267

Customer Support Information
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n
Deny access to pooled facility codes by removing pool dial-out codes
70, 890-899, or any others on your system.
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Create a Disallowed List or use the pre-prepared Disallowed List number
7 (Release 3.1 and later systems only) to disallow dialing 0, 11, 10, 1700,
1809, 1900, and 976 or 1(wildcard)976. In Release 3.1 and later systems,
Disallowed List number 7 does not include 800 and 1800 and 411 and
1411, but AT&T recommends that you add them. Assign all voice mail
port extensions to this Disallowed List. AT&T recommends
assigning Disallowed List number 7. This is an added layer of
security, in case outward restriction is inadvertently removed. (In
Release 3.1 and later systems, voice messaging ports are assigned by
default to Disallowed List number 7.)
If Outcalling is required by voice messaging system extensions:
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Program an ARS Facility Restriction Level (FRL) of 2 on voice mail port
extension(s) used for Outcalling.
n
If 800 and 411 numbers are used, remove 1800, 800, 411, and 1411 from
Disallowed List number 7.
n
If Outcalling is allowed to long distance numbers, build an Allowed List
for the voice mail port extension(s) used for Outcalling. This list should
contain the area code and the first three digits of the local exchange
telephone numbers to be allowed.
Security Alert:
The MERLIN LEGEND system ships with ARS activated with all
extensions set to Facility Restriction Level 3, allowing all
international calling. To prevent toll fraud, ARS Facility Restriction
Levels (FRLs) should be established using:
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FRL 0 for restriction to internal dialing only
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FRL 2 for restriction to local network calling only
n
FRL 3 for restriction to domestic long distance (excluding area
code 809 for the Dominican Republic as this is part of the
North American Numbering Plan, unless 809 is required)
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FRL 4 for international calling
In Release 3.1 and later systems, default local and default toll
tables are factory-assigned an FRL of 2. This simplifies the task of
restricting extensions: the FRL for an extension merely needs to be
changed from the default of 3.
Each extension should be assigned the appropriate FRL to match
its calling requirements. All voice mail port extensions not used
for Outcalling should be assigned to FRL 0 (the default setting
in Release 3.1 and later).
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System Planning