AT&T MERLIN LEGEND Release 4.0 Feature Reference page 67

Feature Reference
Default Toll Table. This factory-set table routes toll calls to numbers that
do not match entries in any of the area code, 6-digit, or 1 + 7 digits. This
table has two subpatterns of up to six routes each, but neither absorbed
digits nor system-prefixed digits are used.
Default Local Table. This factory-set table routes local calls to numbers
that do not match entries in the local exchange tables. This table has two
subpatterns of up to six routes each, but neither absorbed digits nor
system-prefixed digits are used. In Release 3.1 and later, routes
assigned to the default local table are factory set with a Facility
Restriction Level of 2.
The system can have up to 20 tables, 16 of which are fully programmable. The
Dial 0, Special Number (N11), Default Toll, and Default Local tables are factory
set and allow limited programming.
Each table (where appropriate) can have two subpatterns (A and B) with an
associated start time. (The start time for Subpattern A is specified as the stop
time for Subpattern B.) One or the other subpattern is selected based on the
time of day and the subpattern start time. (If both subpatterns have 00:00 start
time, Subpattern A is selected.) Each subpattern can contain up to six routes,
listed in order of preference or cost effectiveness.
In addition, each route has a Facility Restriction Level (FRL) associated with it.
The FRL is used to refine the route selection process further. Each extension or
remote access barrier code or remote access is assigned an FRL from 0
through 6. Each route is also assigned an FRL from 0 through 6. For extensions,
0 is the most restrictive and 6 is the least restrictive level. For line/trunks, 6 is the
most restrictive and 0 is the least restrictive level. An extension can use a route
only if its FRL is greater than or equal to the route's FRL.
Other digits or special characters may be required so the system can route a
call on a particular trunk pool. For example, some companies use an alternate
toll call carrier that requires dialing the telephone number with Pauses and
access codes. Each ARS route may have up to 20 characters that are
automatically prefixed when the user dials a number. The allowed characters
are the digits 0 through 9, , and Pause.
ARS also provides an absorb (ignore) digit capability for each route. For
example, if the central office does not require 1 before an area code, the system
can be programmed to ignore that first digit. Up to 11 characters can be
automatically absorbed when the user dials a number. For 10-digit toll calls, the
prefix 1 must be dialed to indicate to ARS that a toll call is about to be dialed. If
the central office does not require the prefix 1 to be dialed for toll calls, the ARS
digit absorption feature may be used to eliminate the prefix as the destination is
dialed. Initially, all 20 tables are in the list of available tables associated with the
call.
Automatic Route Selection
67