2N ATEUS 501101E, Руководство пользователя

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6.3. Call Sorting Table
6.3.1. Purpose
Almost every application requires that the GSM Gateway‘s behaviour (during outgoing
calls) somehow depends on the called number. Usually, it is not difficult to recognize,
according to a few first digits (the prefix), an international call, mobile network call,
special service call, emergency call, etc. It is possible to enter a line into this table for
each such group of numbers to define:
•
Whether this number can be dialled or is barred (call restriction);
•
How to detect when the dialling is complete;
•
How to bill the call (the so-called pseudo tariff metering);
•
Whether and how the called number is to be modified before being sent to the GSM
network;
•
Whether the record on this call is to be stored in service buffer.
These “rules” can be written into the table, for more details see below.
6.3.2. Sorting Principle
Every table line contains one prefix (of variable length) plus parameters that describe the
behaviour of the GSM Gateway, if the beginning of the called number is identical to this
prefix. However, there is often an exception to the rule – a number that starts identically
but has to be served in a different way.
Example 1: Trunk calls usually start with 0 , but international calls with 00 . It is possible to define
a trunk call by one of the following three ways:
1. The trunk call starts with 01, 02, 03, 04, 05, 06, 07, 08, or 09 – very demanding.
2. The trunk call starts with 0[1...9] – a more convenient way.
3. The trunk call starts with 0 , except for 00 , which is an international call.
The table uses the last of the three ways cited above. There may be any number of
exceptions and the description is very easy:
any table line that starts with the same
prefix but includes one or more additional digits is considered an exception.
Example 2: To bar all international calls except for calls to the Czech and Slovak Republics,
complete 3 table lines – in any sequence – as follows:
00 – international calls – barred
00420 – Czech Republic – allowed
00421 – Slovak Republic – allowed
The said setting has the following advantages:
•
Any further line can be added any time without modifying or checking the remaining
ones. The new line becomes automatically „an exception“ to any of the preceding
ones if it starts with the same prefix.
•
There may be more exceptions to one line and there may be an exception to an
exception again, etc.
Example 3:
0 – international calls – allowed
00 – international calls – barred
00420 – Czech Republic – allowed
004209 – Czech Republic, „VAT services“ - barred
In this example, there are 3 levels of exceptions, but there are even more complicated situations
in reality. Nevertheless, the table is still quite comprehensible.