The GSM-box is necessary to receive the data of the respective sending unit and transfers the data to the service provider/PCO. A GSM-modem is integrated (SIM-card). The data card is provided by the customer. A connection via WLAN is planned in future. Power supply 230 V. Data backup via SD-card available. Please find the technical details under https://www.frowein808.de/products/PERMANENT-MONITORING/.