System Functions and Features as of I7.9
Call routing
201
sy
d-
020
0/3.
0
– I7.
9
– 1
1
.2009
5. 7. 1. 2
Clearing down Exchange-to-Exchange Connections
Digital-Digital (D-D):
The public network sends the PBX a release signal once the external call partners of
an exchange-to-exchange connection have finished the call. The connection is
then cleared down by the PBX.
Without a release signal, the PBX cannot clear down an exchange-to-exchange
connection.
The amount of time between completion of the call and the sending of the release
signal depends on whether the exchange-to-exchange connection is set up end-
to-end within the ISDN network (end-to-end ISDN connection) or whether sections
of it are analogue (non-end-to-end ISDN connection).
At transitions to other networks (for example from leased-line-network to GSM net-
work) it is possible, due to the lack of correct signalling, that an end-to-end ISDN
connection is signalled as a non-end-to-end connection.
End-to-End ISDN Connection
The release signal is sent as soon as the call is completed.
Non-End-to-End ISDN Connection
With non-end-to-end ISDN connections the amount of time between the comple-
tion of the call and the release depends on who set up the connection:
•
If the connection was set up by the PBX user (i.e. from the PBX’s viewpoint an
outgoing call), and the external partner (user C in
) hangs up, it
can take a few minutes for the release signal to be sent.
•
If the connection was set up by one of the external partners (i.e. from the PBX’s
viewpoint an incoming call) and the external partner (user B in
hangs up, the release signal is sent immediately.
Note:
If two announcement services such as sports and weather information
are connected with each other, this exchange-to-exchange connection
will not be cleared down automatically This can lead to high call charges.
Each exchange-to-exchange connection will be cleared down by the PBX after two
hours.
