AT&T MERLIN LEGEND System Reference Manual page 97

Features
Toll Type
System Programming
2-48 Automatic Route Selection
In certain areas the local telephone company requires dialing the prefix 1 for
certain exchanges. In these cases, the exchanges can be assigned to a 1 + 7
ARS table and the 1 + 7 dial setting must be set to 'within area code' so that
people calling numbers in the exchanges do not have to dial the 1.
Specify the type of table (six-digit, area code, local exchange, or 1 + 7) and
the area codes and/or exchanges to be included on the table.
Tables -> ARS -> ARS Input
Specify that 1 + 7 tables should be searched when a leading 1 is dialed.
Tables -> ARS 1 + 7
Specify time of day when calls are routed by using Subpattern B routing
information.
Tables -> ARS -> Sub 8 Start or Sub 8 Stop
Identify the trunk pools (up to six) on which calls are to be routed.
Table -> ARS -> Sub A Pools or Sub B Pools
Assign or remove the FRL associated with each route.
Tables -> ARS -> Sub A FRL or Sub B FRL
Specify the number of digits that need to be absorbed by the system when it
routes calls on an identified route.
Tables -> ARS -> Sub A Asorb or Sub B Absorb
Specify the digits or special characters that must be added by the system to
the number dialed by the user when calls are routed on an identified route.
Tables -> ARS -> Sub A Digit or Sub B Digit