Notes About Restriction Filters - Nortel BCM50 Configuration Manual

416 Chapter 52 Call security and remote access

Notes about restriction filters

A restriction filter is a group of restrictions and overrides that specify the external numbers or
feature codes that cannot be dialed from a telephone or on a line. The restriction filters setting
allows you to assign restrictions in one step as a single package of dialing sequences that are not
permitted.
In addition to restricting telephone numbers, you can prevent people from entering dialing
sequences used by the central office (the public network) to deliver special services and features.
Some of these features provide the caller with dial tone after they have entered the special code
(which often uses # or *), therefore, users have an opportunity to bypass restrictions. To prevent
this from happening, you can create filters that block these special codes.
You create a filter by defining the dialing sequences that are denied. There are also variations of
each sequence that you want users to be able to dial, these are called overrides. Overrides are
defined within each restriction package for each filter.
Once you create the filters, you can assign the restrictions to a telephone, to a line, to a particular
line on a telephone, and to remote callers.
Note: Filter 00 cannot be changed. Filter 01 has a set of defaults. Filters
02 to 99 can be set to suit your special requirements. See
(North America)" on page
• Each programmable filter can have up to 48 restrictions.
• There is no limit on the number of overrides that can be allocated to a restriction. However,
there is a maximum total of 400 restrictions and overrides allocated to the 100 programmable
filters.
• The maximum length of a restriction is 15 digits.
• The maximum length of an override is 16 digits.
• Entering the letter A in a dialing sequence indicates a wild card, and represents any digit from
0 to 9.
• You can use * and # in a sequence of numbers in either a restriction or an override. These
characters are often used as part of feature codes for other systems or for features provided by
the central office (the public network).
• When restricting the dialing of a central office feature code, do not forget to create separate
restrictions for the codes used for DTMF and pulse lines (for example, *67 and 1167).
• Do not string together a central office feature code and a dialing sequence that you want to
restrict. Create a separate restriction for each.
• You can copy restrictions and overrides from one filter to another. You can use a restriction or
override in any number of filters. Each time you use a restriction or override, it counts as one
entry. For example, if restriction 411 exists in filters 01, 02 and 03, it uses up three entries of
the 400 entries available.
NN40020-603 NN40020-603
417.
"Default filters