Matrix Telecom Proton 206, System Manual

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PROTON 206/308 V1 System Manual 21
• Barge-In can also be done by keeping one party in hold. Suppose a trunk call is to be transferred to a busy
station then you can keep the caller in hold mode and Barge-In the destination to inform him about his call.
This is most advantageous feature for the operator.
• However, Barge-In will not work when the destination is in threeparty mode or in dialing state or ringing.
• It will also not work if any station is having call privacy from Barge-In.
Relevant Topic:
1. “Class Of Service (COS)” 36
Behind the PBX Applications
What’s this?
Many times, small and medium range PBX systems are connected behind some bigger PBX systems. Such
applications are used mainly to expand the existing capacity of the big PBX already in use. Stations coming from
the big PBX are used as trunks of the small PBX. There could also be some PSTN trunks coming directly on the
smaller PBX. Such configurations are known as ‘Behind the PBX’ application.
In such situations, it is not easy to implement toll control restrictions.
Consider a simple event
Station 21 of PBX B in the figure above is not given long distance dialing facility. It has access to all the trunks.
Now when he wants to use T2 or T3, which are directly coming from PSTN, he dials ‘0’. He gets PSTN dial tone
and dials the number.
But when he does similar procedure on T1, he gets error tone. Because, in this case when station 21 grabs T1
by dialing a code, he gets dial tone of the PBX A. Now when he again dials ‘0’ to grab PSTN dial tone, PBX
understands it to be a long distance call and since station 21 is not allowed long distance calls, the system
rejects dialing on trunk and gives error tone to station A.
Hence now if station 21 of PBX B is to be allowed external dialing through T1, he should be given long distance
dialing access. If this is done then station 21 may make long distance calls on T1, T2 and T3.
The PROTON 206/308 solves this problem by providing programmable PBX Expansion count for each trunk.
This count is the number of digits to be ignored before toll control check is begun. The PBX Expansion count is
same as the number of PBXs connected between the main PBX and the last subscriber.
In the figure shown, the PBX Expansion count of T1 should be kept 1 and for T2 and T3, it should be kept ‘0’.