This topic should be considered an Advanced Norstar Programming technique.
This FAQ assumes a Modular ICS with a 6.1 feature cartridge and digital trunk interface connected to an ISDN-PRI.
Program the line type for two or more copper trunks (lines) to Pool A. By default, all stations should have access to Line Pool A, it is important to verify this in programming. Also, check to make sure Route 001 uses Pool PRI-A.
Note that the dialing string 911 is included as both a restriction and an override in the initial defaults for restriction filter 01. This arrangement prevents anyone from blocking calls for emergency assistance on lines or sets using the default filter.