Matrix ETERNITY NE, Системное руководство

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360 Matrix ETERNITY NE System Manual
Behind the PBX Application
What's this?
It is common for small and medium PBXs to be connected to larger PBX systems, where the trunks of the larger
PBX are connected to the extension ports of the smaller system. This is usually done for the purpose of expanding
the capacity of the large PBX already in use.
Such configurations are referred to as 'Behind the PBX Application'.
How it works
Consider the following illustration.
PBX-A is connected behind ETERNITY NE. In this 'Behind the PBX' configuration, the Trunk Lines T4, T5, T6 of
ETERNITY NE are connected to the Extensions (SLT) S4, S5, S6 of PBX-A.
However, Trunk lines T1 and T2 of PBX-A are connected directly to the CO.
In such application scenarios, implementing toll control restrictions for the trunks becomes difficult for ETERNITY
NE.
For example: Extension Number 21 of ETERNITY NE in the above illustration is not allowed the facility of long
distance dialing. It has access to all the CO trunks.
When the user of Extension 21 wants to access T1, T2 or T3 (which are direct trunks from the CO to ETERNITY
NE) the user dials '0' (or the Trunk Access Code assigned) and gets CO dial tone. When the user dials the number,
ETERNITY NE applies Toll Control.
Similarly, when the user of Extension 21 tries to grab a trunk T4, T5 or T6 (which are connected to extensions of
PBX-A) by dialing Trunk Access Code '0', the user gets the dial tone of PBX-A. This means, the user of Extension
21 must dial '0' again to grab CO dial tone of the T1 or T2 connected to PBX-A.
However, when the user dials '0' again, ETERNITY NE applies Toll Control. It detects the dialed number as ‘00’ and
interprets this as an attempt to dial a long distance number. Since Extension 21 is not allowed long distance dialing
in its Toll Control, ETERNITY NE rejects dialing on the trunk and plays an error tone to Extension 21.