... of intelligent GPS two way car security system/car alarm system/vehicle alarm system to support complete car realtime tracking, ... door-opening, Voltage Analog Input, Low battery voltage alarm, emergency brake, etc.Backup Battery internal, 12v, 500mAhBackup Time40minutes~90minutesSerial ... , and RS232 connected device Intelligent GPS car alarm system/gps tracking device/ car gps alarm tracker RS3000B1/C1 ...