Section 700 - Operation
Leading Digits Table
The leading digits table considers the initial dialed digits in determining the restriction TRS level.
Up to 10 digits can be considered. The digits may be any number 0, 1-9. In addition a wild card (*) may be used
to occupy any digit position. For instance *11 would consider the numbers 011, 111, 211, 311, 411, 511, 611,
711, 811, 911.
When considering the prefix string, the system will always consider the longest exact match first. For instance,
the prefix string 404 match would be followed before 40.
A wild card is always considered last. For instance if 911 were dialed and both 911 and *11 were prefix strings,
the 911 would be followed.
If additional digits need to be considered, a prefix ID can be used to cross-reference the Analyze Digits Table.
Once the system determines an exact match, the system will determine from this table the number of digits that
are to be dialed and the restriction TRS level. (There are two other entries in the Leading Digits Table - Route
Type and Route Number. These are not used for TRS-only operation.)
Note that TRS operation is a match then restrict feature. If there is no match, there is no restriction. Make
certain that there is a match. As a catch all, use the * wild card.
Analyze Digits Table
If the Leading Digits Table contains a Prefix ID, the system will consider all appearances of this Prefix ID to
look for an exact match. Up to 8 digits are considered (in addition to the prefix dial digits).
Once the system determines an exact match, the system determines from this table the number of digits that can
are expected to be dialed and the restriction TRS level. (There are two other entries in the Analyze Digits Table
- Route Type and Route Number. There are not used for TRS-only operation.)
When ARS is used in the DBS 576 system, TRS also operates.
TRS Class Features
These are the same features as for TRS (see above).
TRS Class - ARS Routing
For each of the 50 TRS classes, a TRS Level of 0-9 may be assigned. (This is not done on a Trunk group basis
since the ARS system determines the trunk group used.)
When a call is originated, this TRS value is used to determine the originator's TRS level. From the dialed
digits, a restriction TRS level (0-8) is determined. If the originator's TRS level does not exceed the restriction
TRS level, the call is restricted. The higher the originator's TRS level, the less the restriction. If the originator's
TRS level is 0, no outside calls are allowed. If the originator's TRS level is 9, all outside calls are allowed since
this will always exceed the restriction TRS value (maximum of 8).
With TRS is used in a system behind another PBX, the PBX access code does not have to be processed
DBS 576 (USA), issued January 1999
Appendix A. ARS and TRS Operation