Alarm Input And Output Port; Alarm Relay Specifications; Bidirectional Talk; Device-End To Pc-End - Dahua NVR21-S2 Series User Manual

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
Connect the NC port of the alarm device to the alarm input port (ALARM) of the NVR.

When there is peripheral power supplying for the alarm device, please make sure it is earthed with
the NVR.

2.3.3 Alarm input and output port


There is peripheral power supplying for the external alarm device.

In case overload may result in NVR damage, please refer to the following relay specifications for
detailed information.

A/B cable of the RS485 is for the A/B cable connection of the speed PTZ.

2.3.4 Alarm relay specifications

Model:
Material of the
touch
Rating
（Resistance
Load）
Insulation
Surge voltage
Length of open
time
Length of close
time
Longevity
Temperature

2.4 Bidirectional talk

2.4.1 Device-end to PC-end

Device Connection
Please connect the speaker or the pickup to the first audio input port in the device rear panel. Then
connect the earphone or the sound box to the audio output port in the PC.
Login the Web and then enable the corresponding channel real-time monitor.
Please refer to the following interface to enable bidirectional talk. See Figure 2-67.
JRC-27F
Silver
Rated switch capacity
Maximum switch power
Maximum switch voltage
Maximum switch currency
Between touches with same
polarity
Between touches with different
polarity
Between touch and winding
Between touches with same
polarity
3ms max
3ms max
Mechanical
Electrical
-40℃ ~+70℃
30VDC 2A, 125VAC 1A
125VA 160W
250VAC, 220VDC
1A
1000VAC 1minute
1000VAC 1minute
1000VAC 1minute
1500V (10×160us)
50×106 (3Hz)
MIN
200×103 (0.5Hz)
MIN
108