Using the PSTN module, the communication capabilities of lares 4.0 control panel can be extended. It allows the sending of voice messages and contact ID when any of the events programmed in the control panel occurs. It is a quick installation module, plugged into the control panel motherboard, and connected to the telephone line through a standard RJ-11 connector. Another connector, always RJ-11, allows the connection of telephones and other devices that use the telephone line, in case of alarm the device is therefore able to start the communications by disconnecting all the other devices that use the telephone line. It can work either as a back-up of 3G module (or GSM module) or as main line.