... module Holux M89 or Royaltek REB-3571I/O Inputs Emergency Button,2xLow Voltage Analog, 2xHigh Voltage Analog, ACC Status, ... -opening, Voltage Analog Input, Low battery voltage alarm, emergency brake, etc.Serial Port RS232 For connecting external intelligent ... of the siren when the alarm is triggered.Emergency Button Support for emergency button to invoke an immediate high-prioritytransmission to the ...