I assume that it is about DIT feature (dedicated inward trunking) - Direct Inward Termination.
Some things to check:
The DITW feature (COP parameter DITW ) with digit prefixing (DGTPR in AMO TACSU) has the same effect in the case of a tie trunk.
Both features may not be used together.
•The feature is only effective in the case of incoming seizure type ATND or HAUS1.
•The COT parameter DIT must be set in the associated trunk.
•The COP parameters DITW, DTN, DTV may not be set when using the DIT feature.
•The COP parameters DTN (incoming seizure dial tone) and DTV (dial tone analysis) have no effect if the DIT feature is activated.
•The HOTRCL feature in AMO FEASU must be set, and a valid DITIDX configured in AMO TACSU and a subscriber number configured in AMO HOTLN.
•In AMO TACSU, the DITIDX must be in the range of 1 to 512; a DITIDX value of 0 acts as if no DIT feature had been configured.
•If no HOTLN number has been entered or if FEASU HOTRCL has not been set or the DITIDX in AMO TACSU has not been entered, the DIT feature is not executed. In this case, the call behaves as if no DIT feature has been configured (i.e. switching system call).
If the assigned DIT station is out of service or if the assigned station number is vacant, the incoming DIT call be routed to the attendant or to the night answer arrangement if no attendant is in service.
If the assigned station is not authorized to receive the call due to ITR group restriction, the incoming DIT call be routed to the attendant or to the night answer arrangement if no attendant is in service.
In ZAND: ALLDATA - check param:
TRDGTPR - Toll restriction for trunk calls with digit prefixing