ELRO FA420DVR 4-ch digital recorder + 500 gb hard disc USERS MANUAL - Manual (Page 10)

Page 10
Signal lines and shielded cables should have tight connections. Avoid false soldering and prevent
oxidation of the solder connection surface.
2.5.2 Selection and Connection of Video Output Devices
PAL/NTSC BNC (1.0V
P-P
, 75Ω) video output and VGA output exist
（
They can operate
simultaneously
）
When using a computer monitor as an alternative surveillance display, pay attention to the following:
1. In order to prolong the life of the equipment, do not leave the monitor power-on for an extended
period of time
；
2. Perform demagnetizing regularly to ensure proper working status of the monitor
；
3. Keep it away from devices generating strong electromagnetic interference.
TV is not a reliable alternative as the video output device. It also requires minimizing the power-on
time and tight control of interference from surrounding power source and devices. Possible electricity
leakage from low quality TV could result in damage to other devices.
2.5.3 Audio Signal Input
AV interface for audio input.
With higher impedance, active pickup is required.
As with video input, the audio transmission line should minimize interference, prevent inadequate
soldering and faulty connections. Pay special attention to protection against a high voltage power surge.
2.5.4 Audio Output:
The parameter of the DVR audio output signal is usually greater than 200mv 1kΩ (AV). It can be
directly connected to low impedance headphones, powered speakers or drive other audio output devices
through an amplifier. If spatial isolation cannot be established between external speakers and pickups, it
could result in a whistling sound. In the event, you may:
1
、
Use pickups with better directivity;
2
、
Adjust speaker volume to the level below whistle threshold;
3
、
Use sound-absorbing materials in the working environment to reduce sound reflection and
improve room acoustics;