AASTRA DT4x2 for MD Evolution User Guide EN - Manual (Page 48)

Outgoing Calls, Busy/No-Answer
MD Evolution – Cordless DT412 / DT422 / DT432 48
Toll Restriction and Least Cost Routing
Usually, you have access rights to the public network and all private
networks to which your facility is connected. You also usually have
the authorization to dial any type of external number, most
particularly a public number.
In terms of the facility programming dictated by your system
administrator, there may be certain external numbers that are
discriminated.
Most particularly, this may apply to numbers for service provided by
the public network, or certain international destinations. An attempt
to dial these numbers would be automatically refused.
Moreover, your facility will also most often be equipped with a Least
Cost Routing (LCR) service for external calls, especially if your
facility is connected to private networks or different public network
operators.
The LCR service therefore automatically ensures that the routing of
external numbers you dial will be processed with the least possible
cost, or managed according to the most optimal calling route.
Note: The numbers dialled using abbreviated dialling are
never subjected to any type of discrimination. If you have a
specific need or question concerning discriminated
numbers, you may ask your system administrator or facility
attendants that the numbers in questions be added to the
list of abbreviated dialling numbers.