Saful PG3 PSTN+ GSM LCD screen doorbell GSM door alarm system Features 1.English blue backlit LCD large screen display,Website: ... prompts,easy to operate.PSTN/GSM,Compatible with dual network alarm,double insurance,more stable. Directly inquiry calls & call functions ... automatic control. 4.Phone (cell phone) or SMS remote host system settings, APP SMS control, beautiful interface, easy to operate. 5 ...