2N BRI Lite/Enterprise v1.1 - Manual (Page 45)

Call Routing Principles 3.2
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 In case the prefix and call time comply with the routing rules, the call is
routed according to the first LCR rule to the module corresponding to the
particular Outgoing GSM group included in the Outgoing destinations list.
 If the selected GSM module is busy or has a low credit, the preceding step is
repeated and the next LCR row is checked.
 In case the selected GSM module is free and has a sufficiently high credit, the
GSM gateway starts dialling the GSM number.
 If the calling subscriber number has an unknown prefix or all routes are busy,
the GSM gateway rejects the call setup request.
 An outgoing call is not billed until the called party answers the call.
 The GSM network signals the off-hook and the GSM gateway transfers this
information to the PBX.
 The gateway is able to generate the AoC tariff pulses during an outgoing call,
which, if the GSM gateway is connected to the PBX, allows for call cost logging
per user.
Incoming GSM Call Routing
Incoming GSM calls are routed by the algorithm described in the following steps and
shown in the figure below:
Incoming calls are processed according to the Mode parameter in the Incoming GSM
calls table. The following options are available:
 Reject/Ignore incoming calls – incoming calls are not routed to
extensions. The call setup request can either be rejected or ignored on the
GSM side (the calling party hears the check ringing tone).
 Report to PC – information on an incoming call is sent to a PC equipped with
the management software. The calling subscriber gets a voice message or the
check ringing tone. The management software then completes the call routing
procedure.
 CallBack – this function helps establish connection on the account of the SIM
card inserted in the gateway. The incoming call is either ignored or rejected.
After the calling subscriber hangs up, the GSM gateway sets up connection to
the defined extension. When the extension answers, the GSM gateway replays
the CallBack message to the extension while establishing connection to the
previously calling GSM/UMTS subscriber. After the CallBack message, the
GSM gateway interconnects the call. If CallBack with incoming call ignoring is
enabled and the calling party fails to hang up within a defined timeout
(default=10s), the CallBack function is disabled for this call and the subscriber
can go on dialling the extension number. Set the CallBack function in the CLIP
routing table.
 If none of the above mentioned options is selected, the AutoCLIP routing table
is checked. If the calling number is found, the call is routed to the extension
whose number is assigned to the calling number in the table.
 In case the calling number is not included in the AutoCLIP routing table, or
the AutoCLIP routing function is disabled, the gateway receives the incoming
call and either replays a voice message or transmits the dialtone to the calling
subscriber. Then the gateway awaits the count of digits necessary for call