2.7.5.14 ACCESS BARRING BY DIGIT ANALYSIS
40 to DSS
These systems are provided with an access barring programme which will allow 5 classes of
barring.
CLASS A Unrestricted
CLASS B
Barred to ISD, STD allowed
CLASS C Limited
access
CLASS D Local calls
CLASS E
PABX calls
Provision is made to store some common allowed numbers which any station may use,
regardless of barring class.
Note that access barring by digit analysis is not applied to the higher group of lines when the
“No Access to Exchange Line Group” facility is programmed.
To provide the access barring facility the following data must be programmed into the system.
CLASS A
No data required.
C L A S S B
ISD code required.
DSS key 40 has the provision to programme one number of up to four digits. In
Australia this is “0011”.
C L A S S C
STD access code(s) and allowed STD and ISD numbers are required.
Data programmed using DSS key 41 allows stations assigned to class C to dial
preprogrammed STD or ISD numbers.
CLASS D
DSS key 41 has provision for up to 12 numbers with as many as 20 digits each. If
a number is longer than the digits programmed it can be
providing the
programmed digits agree with the first digits of the number
STD access code(s) and a number length limiter are required.
DSS keys 42 and 43 are used to programme data necessary to perform STD
barring.
C L A S S E
DSS key 42 is used to programme the maximum number of digits that can be
when making a local call. In the major capital cities in Australia this is
usually
in other areas the maximum number length may vary.
43 is used to programme the barred codes to stop STD calls. There is
provision for up to eight numbers of two digits each. In the centre of a major
capital cities “0” is usually sufficient, however, in outer metropolitan areas or in
the country a more elaborate set of codes will be necessary.
Trunk access code is required.
DSS key 44 is used to programme the trunk access code of up to two digits, that
is, the number
to get an outside line from the PABX. This data, in
conjunction with data programmed using DSS key 34, exchange line type, is
used for last number redial as well as access barring.
COMMON ALLOWED CODES
DSS key 45 is used to programme eight common allowed numbers of up to four
digits each, which can be used by any station independent of the station class of
service. The number
must agree exactly with the number programmed,
therefore this facility allows stations to dial numbers which would normally be
barred, emergency “000” or Telecom service numbers e.g. directory assistance
“01 3”.
The ISD code, the 12
numbers, the eight STD barring codes, the trunk access code
and the common allowed numbers are programmed using the same procedure.
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