6
devices. In the case of external speakers and microphone cannot be achieved
spatial isolation, it is
easy to produce output howling phenomenon. At this point the measures to be taken are:
•
The use of directional better pickups.
•
Adjust speaker volume, making it lower than the threshold to produce the whistle.
•
Multi-use environment using sound-absorbing materials decoration, reduce the
reflection of the sound, improve the acoustic environment.
•
Adjust the layout of pickups and speakers, but also can reduce the occurrence of howling
situations.
2.5.
Alarm input and output connections
Before connecting the device, please note the following:
* Note:
Some Series de
vices doesn’t support
alarm input and output functions.
2.5.1.
Alarm Input
Alarm input is grounding alarm input.
Alarm input requirements for ground voltage signal.
When the alarms are connected to two DVR (WITHOUT HDD) or simultaneously access the DVR
(WITHOUT HDD) or DVR (WITHOUT HDD) and other devices, need to be isolated by relay.
2.5.2.
Alarm Output
DVR (WITHOUT HDD) alarm output cannot be connected power load (no more than 1A), should
constitute the output loop current is too large to prevent damage to the relay. Require the use of
high-power load contactors isolation.
2.5.3.
PTZ
Decoder
connected
•
Must do PTZ decoder and DVR (WITHOUT HDD) common ground, otherwise there may be
Common-mode voltage will lead to control PTZ. Recommended to use shielded twisted pair with
shielding for common ground connection.
•
Prevent high voltage in series, rational layout, and good lightning protection measures.
•
To be incorporated into the 120 ohm resistor in the remote reduced reflection, to ensure signal
quality.
•
DVR (WITHOUT HDD) 485 AB line cannot be connected with other 485 output.
•
AB line voltage between the decoder requires less than 5V.
2.5.4.
Front-end device requires grounding
Poor grounding may cause the chip to burn.
2.5.5.
Any type of alarm input
The alarm output unit interface is a normally open type.
8 external alarm interface schematic:
Summary of Contents for Indigo JRC-27F
Page 1: ...DVR WITHOUT HDD User s Manual Version 1 01...
Page 106: ...100 Figure 5 29 Figure 5 30...
Page 109: ...103 Figure 5 32 Figure 5 33...
