Emergency telephone with bus system. For communication between main unit and car unit. Only four wires are needed. To achieve a higher level of availibility the option of using both PSTN and GSM and let them work together is possible. The integrated battery ensures continued operation in case of power failure. A regular condition test is made and an alarm will be sent if the battery needs to be replaced. Meets EN81-21, EN81-70 and EN81-72 standards. Car unit is ordered separately.
