... 315mhz Functions & Features of the GSM Alarm System :1.Touch keypad; Big LCD displays, NO EXTERNAL GSM ANTENNA ON THE PANEL2 ... doorbell , user can add wireless extra indoor/outdoor siren, wireless keypad etc to the system9.Alarm priority, Reset, activate and disable ... version,like Polski , Cestina, Spanish, Russion etc, which are customized by clients Specification: 1.Working power: AC=100~240V, DC ...