Nortel SRG200 Configuration Manual page 179

Table 17
Provisioning details for this case (Part 2 of 2)
Region
1, 2, 3 All CDP numbers must be sufficiently long to allow unique
termination of the calls. That is, every main office/branch
office region requires its own LSC to ensure that all numbers
are unique.
1, 2, 3 Prefixes for branch offices for regular calls are required. May
have additional prefixes for E-911 calls, if required, or may
share prefixes.
1 All branch offices are provisioned at the NRS to route all calls
through the main office.
1 Main office sends all CDP calls to destinations that are not its
own branch office to the NRS with unchanged dialled digits.
1 Main office sends all CDP calls to destinations that are its own
branch office to the NRS with a specific gateway prefix in front
of the dialled digits.
1 All branch offices delete the prefix and terminate the calls.
May be to a local set or to a trunk.
2,3 Similar configuration, as above, applies to regions 2 and 3.
Main Office Configuration for SRG200/400 Release 1.5
Bandwidth Management
Provisioning detail
Page 179 of 254
Configuration Guide