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SIP Operation Manual V2.6
If Level 1 is set to prohibit dialing any number with prefix 0, then any level below 1 (including
Levels 2 to 5) is also prohibited. Since Level 0 is not restricted to any prefix, therefore at level 0
users can dial a number with the prefix 0.
Principle: Downward Restriction —If the users at a higher level cannot dial a number with a
certain prefix, then users at lowers level also cannot dial a number with the same prefix.
Long Distance Exception Table
This table handles any exceptions to the long-distance call table.
Instruction:
According to the Long Distance Control Table, users at Level 2 are prohibited to dial a number with
the prefix 0. But, if a prefix 09 is set in the Exception Table, then the users at Levels 1 and 2 could
then dial any number with the prefix 09.
According to the Long Distance Control Table, users at Level 0 are prohibited to dial a number with
the prefix 0204. But, if the number 020488988 is set in the Exception Table as above, then users
could then dial this number.
Principle: Upward Opening —If the users at a lower level can dial a number with a certain prefix,
then the users at higher levels can also dial a number with the same prefix.
CPT/Cadence Settings
CPT/Cadence setting parameters serve as the basis of an FXO interface to determine whether or not a
PSTN-call receiving party has hung up the phone. If the following parameters differ from the parameters
of the actual assigned lines, it could cause the FXO to continue to engage a line.
Busy Tone Cadence Measurement
