220 Series 25
Operating Principles
The communicator can choose its primary channel (the factory setting is PSTN). It supplies the line and ringtone voltage for
incoming calls and decodes dial tones (DTMF). The simulated PSTN line provides a backup for the burglar alarm panel or other
terminal should the main PSTN line fail. Calls CANNOT be switched between PSTN and GSM, or vice-versa, while they are in
progress. Operating priority (as programmed) determines how the communicator handles SMS and voice messages, and calls with
devices connected to terminals LI (for example, a burglar alarm panel).
The communicator is NOT able to decode pulse dialing.
To prevent undesired use of the simulated line via GSM, the device generates a double beep during voice calls. It does so
after 5 minutes and every 30 seconds thereafter.
PSTN channel
If the voltage on the PSTN terminals (LE) falls below 2.5 V DC (± 20%) for 10 to 3600 seconds (programmable value), the devices
connected to terminals LI are switched to the GSM network. When PSTN service is restored, the communicator switches back
to the PSTN line, again after a programmable delay.
It is possible to force communications to the GSM/cellular data network, even when PSTN is present, by entering a
programmable prefix (factory setting “9999”) ahead of the phone number dialled by the panel (for further details, see Dialing
Prefix in “PSTN/PTM” on page 51).
If the device is on the simulated GSM line for any reason, the prefix is deleted from the number (if present).
Example: the communicator makes independent calls only on the GSM/cellular data network, and not on the PSTN line.
All communications made on the external PSTN line (terminals LE) come from the line connected to terminals LI, and are not
modified. It follows that the PSTN line connected to LE is not considered a communications channel pursuant to EN 50136.
GSM channel
This provides the devices connected to the LI terminals with a simulated line if GSM reception is detected. If there is no GSM
coverage, it switches to PSTN.
Number dialled by
panel
Phone line
Number with IP Receiver
on GSM Path enabled
Effect
0123456789 PSTN None PSTN voice call to 0123456789.
99990123456789 PSTN 0123456789 Contact ID call on cellular data network.
99990123456789 PSTN None Voice or Contact ID call on GSM to 0123456789.
99990123456789 Simulated GSM 0123456789 Contact ID call on cellular data network.
99990123456789 Simulated GSM None Voice or Contact ID call on GSM to 0123456789.
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