DVR systems DVRxx04HF-U Series - Manual (Page 46)

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a. Ensure the decoder has the same grounding with DVR, otherwise you may not control
the PTZ. Shielded twisted wire is recommended and the shielded layer is used to connect
to the grounding.
b. Avoid high voltage. Ensure proper wiring and some thunder protection measures.
c. For too long signal wires, 120Ω should be parallel connected between A, B lines on the
far end to reduce reflection and guarantee the signal quality.
d. “485 A, B” of DVR cannot parallel connect with “485 port” of other device.
e. The voltage between of A,B lines of the decoder should be less than 5v.
4. Please make sure the front-end device has soundly earthed.
Improper grounding may result in chip damage.
3.8.1 Alarm Input and Output Details
Important
Please refer to the specifications for the alarm input and output channel amount.
Do not merely count the alarm input and out channel amount according to the ports
on the rear panel.
Figure 3-6
In the first line, from
the left to the right,:
1，2，3，4，5，6，
7，8，9，10，11，
12，13，14，15，16 ALARM 1 to ALARM 16. The alarm becomes active in low voltage.
In the second line,
from the left to the
right:
NO1 C1，
NO2 C2，
NO3 C3，
NO4 C4,
NO5 C5 NC5 The first four are four groups of normal open activation output (on/off
button)
NO5 C5 NC5 is a group of NO/NC activation output (on/off button)
CTRL 12V Control power output. You need to close the device power to cancel
the alarm.