ZETRON 748, Technical Manual

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Operation
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PBX OPERATION
Operating an interconnect that is installed on a PBX has a different set of requirements than one
installed on a conventional PSTN connection. The Model 748 provides some PBX specific
programming to meet these needs. Based on programming and what the mobile dials, the Model 748
can distinguish between an internal or an external call or a direct PSTN connection. This allows the
toll restrict programming to be applied only to calls dialed outside of the PBX.
Internal Calls
The Model 748 provides a way to determine if the mobile is placing an internal call or trying to go to
an outside line. When a mobile has accessed a phone line configured as PBX, the first digit dialed by
the mobile is scanned against
PBX outside line digit for a match. If no match is found, the call is
flagged as a PBX internal call. If a match is found, then it is flagged as an PSTN type and all
programmed toll restrictions apply starting with the second dialed digit. Up to 4 digits may be
entered as
PBX Outside line digit (default is none). For internal calls, the Model 748 will regenerate
digits equal to PBX Extension length (default = 3). PBX inside calls are considered local calls for all
users. All DTMF is passed through (digit blapping is disabled). Hook flash is valid for all users who
have this enabled (no toll restrict qualifier like on PSTN calls). Hook flash on internal calls does not
go into regeneration.
External Calls
When a mobile dials the first digit and it is used to select an outside line, the Model 748 flags the call
as a PSTN call. The first or leading digit (used to select the outside line) is now ignored as if it was
never dialed. As additional digits are dialed, they are monitored according to the current toll restrict
programming for that user. External calls though a PBX extension line follow all the same rules as a
call on a direct PSTN connection.