AT&T Merlin II Release 3 System Manual page 76

CONSIDERATIONS
RELATED FEATURES
For example, to prevent billable calls to the 976 exchange in any area code
(976 is an exchange that is used for telephone services such as time, weather
reports, and lottery announcements), you can enter three wildcard characters
to represent the area code so that the system denies access to 976 exchanges
in every state.
Each of the eight Disallowed Lists can contain numbers up to 12 digits,
including wildcard characters (Hold).
Wildcard characters can be used to represent any area code or combination
you require.
Users cannot dial a number on an Allowed List if it matches a number on a
Disallowed List that is assigned to your phone.
If a number is assigned to a System Speed Dial code and is also on the
Disallowed List, the number will not go through unless the System Speed
Dial code is marked.
Allowed Lists
System Speed Dial
MERLIN II System Features 3-47