Technical information

Small Business Communications Systems
5-10 Issue 7 June 2001
Default Disallowed List
By default, Disallowed List #7 contains the following entries, which are frequently
associated with toll fraud:
 0
 10
 11
 976
 1809
 1700
 1900
 1ppp976 (where each p represents any digit)
 *
This list is automatically assigned to any port that is programmed as a VMI port.
The system manager should assign Disallowed List #7 to any extension that does
not require access to the numbers in the list.
Assigning a Second Dial Tone Timer
A second dial tone timer can be assigned to lines and trunks to help prevent toll
fraud.
NOTE:
This timer can be used with star codes, which are discussed earlier in this
chapter.
If the timer is assigned, and if the user dials a certain set of digits, the CO provides
a second dial tone to prompt the user to enter more digits. This ensures that digits
are dialed only when the CO is ready to receive more digits from the caller.
Therefore, the risk of toll fraud or of the call being routed incorrectly is reduced.
Setting Facility Restriction Levels
Facility Restriction Levels (FRLs) can help prevent toll fraud. Some FRLs are
already set to a default value before the product is shipped to the customer. Other
FRLs can be set by the customer.