Instruction manual

Tandem Trunking
To gain access to an ARS routing facility, the tandem trunk’s “station” FRL must be equal to
or greater than the route’s FRL. Thus, a tandem trunk with a FRL of 0 has the least ARS
privileges, while a FRL of 3 provides the most privileges.
If the restriction level of the
tandem trunk is less than all route FRLs, reorder tone is returned to the calling party.
Dial Access: No toll restriction is provided for tandem trunk calls. However, access to
outgoing facilities can be controlled via the “allow dial access” option in the outgoing trunk’s
administration.
Tandem Trunk calls receive the following treatment when attempting dial
access of System 25 facilities:
● If the requested trunk pool is dial accessible, an outgoing trunk is selected and the
call proceeds normally.
● If the requested trunk pool is not dial accessible, reorder tone is returned to the
calling party.
Any attempt to dial an outgoing trunk pool by non-tandem tie trunks (that is, tie trunks whose
trunk number does not begin with 9) results in reorder tone being returned to the calling
party.
Paging System Access: Tandem trunks can access paging ports (auxiliary or CO trunk
interface), as long as the paging ports are dial-accessible.
Station Message Detail Recording (SMDR): After accessing an outgoing facility, the tandem
trunk’s Facility Access Code (FAC) will be recorded in the STN field on the call’s SMDR
record. If the tandem trunk has no FAC, then the 4-digit trunk number (9xxx) will be
recorded in the STN field. All other SMDR fields are unaffected.
Administration Requirements
Except for the need to specify the trunk number as described above, administration of
tandem trunks is the same as for any other tie trunk.
Hardware Requirements
Only dial-in tie trunks (types 1003-1008) may be used for tandem trunking.
2-331