Dahua HDCVI series, User Manual

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74
Earth cable.
485 A/B 485 communication port. They are used to control devices such as
decoder.
120Ω should be parallel connected between A, B lines if
there are too many PTZ decoders.
T+,T-,R+,R- They are four-wire full-duplex RS485 port
T+ T-: output wire
R+ R-: input wire
3.7.2 Alarm Input Port
Please refer to the following sheet for more information.

Grounding alarm inputs. Normal open or Normal close type)

Please parallel connect COM end and GND end of the alarm detector (Provide
external power to the alarm detector).

Please parallel connect the Ground of the DVR and the ground of the alarm detector.

Please connect the NC port of the alarm sensor to the DVR alarm input(ALARM)

Use the same ground with that of DVR if you use external power to the alarm device.
Figure 3-2
3.7.3 Alarm Output Port

Provide external power to external alarm device.

To avoid overloading, please read the following relay parameters sheet carefully.

RS485 A/B cable is for the A/B cable of the PTZ decoder.

T+,T-,R+,R- are four-wire double duplex RS485 port.
T+ T-: output wire
R+ R-: input wire
Relay Specification
Model:
JRC-27F
Material of the
touch
Silver
Rating
（
Resistance
Load
）
Rated switch capacity 30VDC 2A, 125VAC 1A
Maximum switch power 125VA 160W
Maximum switch voltage 250VAC, 220VDC