... Level Voltage, 2xHigh Level, ACC, Engine, Door Open, Brake , 2x A/D (10bit digital,5V,12V,24V,30V ... opening, Voltage Analog Input, Low battery voltage alarm, emergency brake, etc.Backup Battery internal, 12v, 500mAhBackup Time40minutes~90minutesSerial PortRS232Two ... , fix bar, and RS232 connected device Intelligent GPS car alarm system/gps tracking device/ car gps alarm tracker RS3000B1/C1,support ...