ZETRON 748, Technical Manual

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Operation
025-9368H 37
Universal Plan
The “Universal” toll restrict plan or mode is designed to allow the system operator to define a toll
restrict plan to meet local requirements. It uses two prefix tables (up to 10 entries each) to define a
filter or plan. As digits are dialed, the Model 748 will scan the entries in the table for a match against
the dialed digits. One table is defined as “Allowed” (TblA) and the other as “Restricted” (TblB).
Each user (radio) whom you wish to restrict dialing can be assigned which table (TblA or TblB) is to
be scanned when dialing. Entries in the table can be 2 - 4 digits in length. Valid digits are 0 - 9. Wild
card or don't care digits can also be defined using the “*” character, anywhere in the string.
Two other parameters are used with the “Universal” plan. Minimum regenerated digits and
Maximum regenerated digits . These two values set the range for how many digits the mobile may be
required or allowed to dial. The number of digits required for the Model 748 to evaluate the prefix
table is based on the setting of
Minimum regenerated digits . If set to less than 4, then scan is started
using Minimum regenerated digits and continues until greater than 4 digits have been dialed. The
digits will always be evaluated when 3 and 4 digits have been dialed.
If the minimum number of digits is not met, the call will always be terminated as toll restricted. If
the Maximum number of digits is exceeded, regeneration is terminated. If the users Toll restrict type
is None, mobile to phone audio is enabled, otherwise the call will be disallowed.
Dial in termination (when the Model 748 stops regenerating digits and enables the mobile to phone
audio path) is determined using timers and/or a termination digit (“*”). If no DTMF digits are
received from the mobile for the programmed
DTMF interdigit time , and the minimum number of
regenerated digits has been met, the Model 748 will drop out of regeneration and enable the mobile
to phone audio.
North American Plans
Phone systems in most areas of North America follow a specific format for a telephone number. A 3
digit Area code followed by a 3 digit CO code followed by a 4 digit extension number. The area
code defines a region or area. A CO code is the local Central Office to which your phone line is
connected. The extension number is your specific line or telephone from the local CO.
The first dialing plans established in North America made a distinction between local CO codes
(Central Office) and Area Codes. As a number was dialed the decoding circuits could then route the
call based on the first 3 numbers. Based on the 2nd digit, you could distinguish between a local CO
code and an Area Code. Local CO Codes and Area Codes were not interchangeable for this to work.
This also limits the total number of unique telephone numbers. As regions of North America run out
of unique telephone numbers and equipment upgrades take place, a switch to interchangeable or
New CO Codes is possible. It also means that any 1+ or 0+ number requires 10 digits to follow. The
Model 748 supports both dialing plans.
Prefix table
The North American plans support use of a Prefix table . In some areas, the local phone companies
have two levels of toll calls. Ones that require a 1+ or 0+ and Local Zone calls that do not. To
restrict or block Local Zone calls, a
Prefix table can be built using any of the 999 possible prefixes.
The table can be set up as either “Restricted” or “Allowed” prefixes. If a mobile places a call that is