AT&T MERLIN LEGEND Communications System PBX System Planning Manual page 150

Features
ARS Table Matching
Note: If the local telephone company requires a 1 to be dialed before placing
calls to some 7-digit numbers, setting up 1 + 7 Tables speeds up call
processing. However, users need to be instructed to dial the 1 if these tables
are programmed and the ARS 1 + 7 Dial setting is set to "within area code."
Users have two options for placing calls to 1 + 7-digit numbers:
Users can dial 1, dial the 7-digit number, and wait for ARS to recognize after
a time-out delay that no more digits are being dialed.
Users can dial 1, dial the 7-digit number, and then press #. When the dialing
sequence is ended with a #, the system knows that the user is finished
dialing and eliminates the time-out delay.
Tables 17 and 18, the Default Tables
There are two default tables, one for toll calls and the other for local calls. These
tables minimize the time it takes to plan and program ARS because you don't
have to record the area codes and exchanges.
Table 17, Default Toll Table, routes toll calls to all area codes that aren't listed
in Tables 1 through 16.
Table 18, Default Local Table, routes local calls to all exchanges that aren't
listed in Tables 1 through 16.
Tables 19 and 20, the Special Number Tables
The Dial O Table (number 19) routes calls when a user dials O. If the
international dial code 011 is not included in any other table, calls are routed
via the Dial O Table. You can specify the route to which dial O calls should be
routed.
The N11 Table (number 20) routes calls to these numbers: 411,611, 811,
and 911. These calls are always placed on the main pool (the factory-set
pool access code is 70).
To place a call in a system that has ARS, a user dials a dial-out code (usually
a 9) followed by the telephone number. The system determines the best route
for the call by checking the telephone number dialed against the numbers
(digits) in the ARS tables. ARS eliminates the tables until it finds one containing
a match.
For example, if a user dials O, ARS eliminates all tables except the dial zero
table and places the call using that table's programmed routes.
If a user dials 1-202-555-1234, ARS recognizes that it is a toll call (a 1 followed
by 10 digits) and therefore eliminates all exchange tables.
ARS then checks the Area Code Tables and 6-Digit Tables for a match. If it finds
a match on a 6-Digit Table, it checks the Area Code Tables for a match and
routes the call. If a match is not found on any of the programmed Area Code or
6-Digit Tables, the call is routed according to the Default Toll Table.
System Features 4-45