Optiview DVRTT PRO Series Operation Manual page 22

Chapter II
5) RS232 port Connection.
RS232 port is connected to PC and other devices for specific function and After Sales purpose.
6) USB port Connection
It consists of 1 USB (Front), 1 USB (Rear), its supported devices are such as USB mouse, USB
external HDD and USB memory stick
7) ALARM IN/OUT(SENSOR) Connection
* Alarm Input 1~4CH
When an event happens DVR operates by using external device.
Sensor, Switch signal (Signal GND) are connected terminal block.
Ref : Spec. Max 6V/50mA
* Alarm Output 1CH
It can be on/off external device as buzzer, headlamp etc.
Alarm input mode consists of NORMAL OPEN and NORMAL CLOSE.
Ref : Spec. Max24V/2A
* RS485
Through Half-duplex serial communication, remote controlling is available using control system
as external device, control keyboard.
In addition, it is available to control PTZ (Pan/Tilt/Zoom) camera.
it is connected RS485 +,- of DVR.
22