Advertisement
If the trunk or tie line is to be used for both voice and data then another procedure must be
followed. Modems are grouped into a pool and are switched into a connection when required,
i.e. when a data call is in progress.
1.1.3. Data Communication over a Digital Route
A data connection can be established over a digital trunk or tie line to a data party located in
another PBX or in the PSTN. The digital trunk or tie line is connected to a Digital Trunk Unit
(DTU).
If the data party is connected via a modem to an ALC, then the external party must also have
a modem connection. The modem's modulated carrier signal is digitised by the ALC and are
transferred over the digital route as `voice' samples. Incoming and outgoing data calls can be
allowed without further requirements.
If a data party is connected to a DLC, then an outgoing data call is established by dialling the
trunk or network access code of a digital route. The connection between the DLC and the
DTU is made directly. An incoming call can be directly connected to the DLC after analysing
the incoming number.
In this way a fully digital connection between the calling data party and the destination data
party in different networks is possible.
If the external data party in the opposite network is connected via an analogue line to the
external network, a modem must still be used. By means of compatibility check modem pool
dialling is possible as described in the part above.
1.2.
TEXT COMMUNICATION
The ISPBX offers a transparent path through a network (once a path has been established
between two ports, the data that is transferred between the ports is not processed). Text can
therefore be transferred as analogue or digital signals.
1.3.
IMAGE COMMUNICATION
The ISPBX offers a transparent path through a network (once a path has been established
between two ports, the data that is transferred between the ports is not processed). Images
can therefore be transferred as analogue or digital signals.
1.4.
BOUNDARIES, OPTIONS, TIMERS
For some facilities, certain boundaries, options or timers are important. These parameters are
4
Advertisement
