1.9 Toll Restriction (TRS)/Call Barring (Barring)Features1.9.1 Toll Restriction (TRS)/Call Barring (Barring)DescriptionTRS/Barring can prohibit an extension user from making certain trunk calls by COS programming. It is appliedwhen the user goes off-hook, a trunk is seized and then a dialled number is sent to the trunk.Each COS is programmed to have a TRS/Barring level for each time mode (day/lunch/break/night).There are seven levels available. Level 1 is the highest level and level 7 is the lowest. That is, level 1 allowsall trunk calls and level 7 prohibits all trunk calls. Levels 2 through 6 are used to restrict calls by combiningpreprogrammed Denied and Exception Code Tables.Denied Code TablesAn outgoing trunk call made by an extension with a level between 2 and 6 is first checked against the applicableDenied Code Tables. If the leading digits of the dialled number (not including the Trunk Access number) arenot found in the table, the call is made. There are five Denied Code Tables, one for each of Levels 2 through6 respectively.Complete every table by storing numbers that are to be prohibited. These numbers are defined as deniedcodes.Exception Code TablesThese tables are used to override a programmed denied code. A call denied by the applicable Denied CodeTables is checked against the applicable Exception Code Tables, and if a match is found, the call is made.There are five Exception Code Tables, for Levels 2 through 6 respectively.Complete every table by storing numbers that are exceptions to the denied codes. These numbers are definedas exception codes.TRS/Barring Override by System Speed DiallingIf the call is made using System Speed Dialling, the call can override the TRS/Barring. Each COS isprogrammed to have a TRS/Barring level for System Speed Dialling.Once this feature is set, it permits all extension users to make System Speed Dialling calls with the level forSystem Speed Dialling. Any extension which sets Extension Dial Lock can also make a call using SystemSpeed Dialling.® 4.11 [2-7-1] Class of Service—COS Settings—TRS— TRS Level for System Speed Dialling® [300] TRS/Barring Override by System Speed DiallingTRS/Barring LevelThe TRS/Barring level is determined by the telephone codes set in the Denied Code Tables and ExceptionCode Tables.As shown in the table below, the Denied Code Tables for the higher levels are applied to all levels below it,and the Exception Code Tables for the lower levels are applied to all levels above it.Denied Code Tables*1 Exception Code Tables*2Level 1 Not Programmable Not ProgrammableLevel 2 Table for Level 2 Tables for Levels 2 through 6Level 3 Tables for Levels 2 and 3 Tables for Levels 3 through 6Level 4 Tables for Levels 2 through 4 Tables for Levels 4 through 6Feature Guide 1271.9.1 Toll Restriction (TRS)/Call Barring (Barring)
