User manual

3.2.5. Call Routing
According to a record found in the Call Sorting Table, call is routed to GSM or PSTN
network or bared. If the required network is not accessible, GSM gateway starts to send
busy tone or some special tone (PIN required etc.). Otherwise, the GSM Gateway
transmits the received number into the right network. Description for the case of PSTN
follows.
3.2.6. Connection Making and Establishing
Remember that the PSTN line is already off hook (see chapter 3.1.2, last note). In this
moment, GSM gateway checks how long is PSTN line off hook. If parameter 701 is over,
GSM gateway hangs up for a moment, using parameter 702. (This happens when a
dialling was very slow.) Next, whole number is repeated to the PSTN network (or a
number changed by “take away” and “append” parameters). DTMF is used always, even
if pulse dialling was received. Next, PSTN network is making a connection. During this
time, the subscriber may hear tones from PSTN. Next, the subscriber usually hears the
ringing tone
or another signal transmitted by PSTN network.
3.2.7. The Call
During the PSTN call, incoming calls from GSM network are refused. (This is important
because GSM gateway is not able to serve two calls at a time. Without refuse, calling
party hears ringing, but it is not possible to ring to PBX.)
3.2.8. Tariff pulses
During the outgoing call to PSTN, tariff pulses, if present, are passed from PSTN to PBX.
Pseudo-tariff parameters in the Call Sorting Table are ignored.
3.2.9. Connection Termination (End)
GSM Gateway registers the on-hook (the current flow stops) and switches to its default
state. It is important to secure that PBX will always hang up the line. The time of PSTN
call is not limited by parameter 158.
3.2.10. Subscriber’s Disconnection (Power Down)
If a subscriber blocks the GSM Gateway by seizing the line without dialling a number, or fails to
hang up after the call, he or she will get the busy tone
first and then is
disconnected (Power Down status).
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