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activity is detected over the transmit and/or receive lines within a certain, programmable time
period, the SOPHO-SET or LAM sends a message to clear the call. This facility can be offered
on outgoing and on incoming data calls.
4.7.
DATA PROTECTION
A data connection between two data terminals uses synchronisation signals for the
communication protocol. If a third party (for instance another extension, or an operator) is
able to break-in on the connection, the synchronisation signals can be disturbed and the
synchronisation between the data terminals is lost. Also a call waiting indication can have this
effect. Therefore this interruption must prevented. This can be achieved in different ways:
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Both incoming and outgoing calls over a route are automatically data protected by setting
the general route option `data protection applied' true.
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A DNR can be data protected by assigning FCM 04 (data protected) to the DNR. Every
call made by or routed to the DNR is automatically data protected.
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A DNR can determine if the data protection must be applied. If the DNR is assigned FCM
05 (data protection entitled), the extension user can dial a prefix (initial or enquiry dialling)
for dial up data protection. If this data protection is successful, the user receives dial tone
and a normal call setup is possible. Only for this call the connection is data protected. After
the call has been released the data protection mark is erased and must be set again for a
next data protected call.
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If an IBSC is used that is not for speech then it is impossible for a speech oriented third
party to break-in to the connection.
Note: The compatibility value with `data' indication is NOT used for making a call data
protected. It is only used for the downloading of the interface parameters.
4.8.
DOWNLOADING
Downloading is used for sending predefined settings from the ISPBX to a terminal. This
downloaded data can be used to set the interface characteristics of a data terminal: either
SOPHO SET or LAM.
Before the communication between the data port of the SOPHO-SET or the LAM and the
data terminal can be correctly implemented, the interface between the two devices must be
correctly programmed. This programming can be performed locally via the keypad of the
SOPHO-SET or via the data terminal (interactively) connected via the interface. It is also
possible to download the interface characteristics. In this case the settings of the interface are
collected from the compatibility value that is assigned to the DNR of the data port.
Via the command CHAGCV the DNR of the data port can be assigned to a compatibility value.
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