DVR systems DVRxx04HF-A Series - Manual (Page 50)

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485 A/B 485 communication port. They are used to control devices such as
PTZ. Please parallel connect 120TΩ between A/B cables if there are
too many PTZ decoders.
3.8.2 Alarm Input Port
Please refer to the following sheet for more information.
z
Normal open or Normal close type.
z Please parallel connect COM end and GND end of the alarm detector (Provide external
power to the alarm detector).
z Please parallel connect the Ground of the DVR and the ground of the alarm detector.
z Please connect the NC port of the alarm sensor to the DVR alarm input(ALARM)
z Use the same ground with that of DVR if you use external power to the alarm device.
Figure 3-10
3.8.3 Alarm Output Port
z Provide power to peripheral alarm device.
z To avoid overloading, please read the following relay parameters sheet carefully.
z RS485 A/B cable is for the A/B cable of the PTZ decoder.
Relay Specification
Model: JRC-27F
Material of the
touch
Silver
Rated switch capacity 30VDC 2A, 125VAC 1A
Maximum switch power 125VA 160W
Maximum switch voltage 250VAC, 220VDC
Rating
（
Resistance
Load）
Maximum switch currency 1A
Between touches with same
polarity
1000VAC 1minute
Between touches with different
polarity
1000VAC 1minute
Insulation
Between touch and winding 1000VAC 1minute
Surge voltage
Between touches with same
polarity
1500V (10×160us)
Length of open
time
3ms max
Length of close
time
3ms max