PHONE LINE MANAGER 16 X 4
14.Call Barring (Toll Restriction)
14.1About Call Barring
The Call Barring (or Toll Restriction) feature lets you bar specific extensions from calling certain types of phone numbers (or prefixes). This feature is most commonly used to bar toll calls,
When Call Barring is operating, the system consults a Call Barring Disallow Table of phone numbers (or prefixes) each time a call is placed. It scans the table as each digit is entered. If a match with the Disallow Table is found, the call is denied. If no match is found, the call is permitted. Most commonly a Disallow Table will include the prefixes “1”
Exceptions to the Disallow Table are needed to allow users to call
Creating toll restrictions requires two steps. First you will need to create one or more Disallow and Allow Tables. Then you will need to assign individual extensions to the appropriate table(s).
The system can store up to three
14.2 Call-Barring (Toll-Restriction) Details
As an extension dials each digit, the Phone Line Manager 16 x 4 scans the complete sequence of digits dialed to check if the extension is barred from dialing the sequence. If the extension is restricted from dialing the number, the outside line is immediately released and the person at the extension will hear the fast error tone.
A special case can arise if an outgoing call is made from an unrestricted extension and then transferred to a restricted extension. If the extension were to dial another digit, the unit would normally examine the complete sequence of digits dialed and determine that the extension is not allowed to make the call. The extension would be disconnected from the outside line. A special provision has been made to the operation of the Phone Line Manager 16 x 4 such that the it will not check the call barring restrictions on a transferred call unless and until the extension flashes in order to place the call on hold or transfer the call. This allows the caller to enter additional digits (perhaps to a remote
A second special case can arise if the outside lines are configured to allow a switchhook (flash) to be sent to the outside line. A switchhook to an outside line may be needed to affect certain features like Call Waiting. However, some Central Office switches may give a new dial tone in response to the switchhook. In this case, the caller could possibly dial an allowed number, send the switchhook, and then dial a restricted number. The Phone Line Manager 16 x 4 is only able to examine the digits dialed starting at the beginning of the sequence and the call would not be barred. If this is a concern, you may want to prohibit the switchhook from being sent to an outside line (see Section 6.3).
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