21. What are the ways of installing and using the infrared lamp?
A: Usually, it should be installed beneath the camera.
B: The power supply is AC130V-AC260V
22. How shall we classify the multimeter?
A: Digital multimeter
B: Analogue multimeter
23. How shall we choose the measuring grade place while using the multimeter?
ACV: Alternating Current Voltage grade Ω Resistor grade
ACA: Alternating Current grade →|- diode grade
DCV: Direct Current Voltage grade DCA: Direct Current grade
24. How shall we choose the range while using the multimeter?
A: If the range of the tested figure is not known, the maximum range should be chosen.
B: If the range is known, the specific range should be appropriately chosen to enhance the precision.
25. How to use a multimeter for short and circuit break detection of lines during tertiary network cabling construction?
Use the resistor grade of the multimeter to test the closed circuit and short circuit.
26. How shall we use the multimeter to test the power supply of the monitor device in the process of maintaining a tertiary network?
A: Visual-audio controller. Power supply: input AC220V the board of power supply output +5 (3 pieces) -5 (one piece)
B: Control the power supply of the mainframe: 220V
27. How shall we use the digital multimeter to measure alternating current voltage?
To choose ACV 750V grade
28. How shall we use the digital multimeter to measure direct current voltage?
To choose DCV 20V grade
29. What is the way of correctly shutting down the digital video recorder?
A: Open the peripheral equipment first, then open the mainframe.
B: Shut down the mainframe first, then shut down the peripheral equipment.
30. How shall we achieve simple maintenance and management of the digital video recorder?
A: Check each connected line.
B: Clean dust regularly.
C: Sort out the hard desk drive of the digital video recorder regularly.
31. How to deal with a sudden power failure when the hard disk recorder is running?
A: Shut down all the power supply of peripheral equipment first.
B: When the electricity comes to renew, open peripheral equipment first and then open the mainframe to power in order.
C: Make the system self-tested and manipulate the operating system.
32. What is the function of the sound card of the digital video recorder?
To realize the modular and digital transformation of frequency signal.
33. What is the function of the connector in the sound card of the digital video recorder?
A: SPK B: LINE IN C: MIC
A: sound output B: input linearization C: microphone input
34. How shall we classify the speaker?
A: Active Speaker
B: Passive Speaker
35. How shall we choose a speaker?
A: Active Speaker, Passive Speaker
C: Work and power
E: Sound quality
36. What is the function of the capture card of the digital video recorder in the server-side surveillance system?
Collect video signals and transform analog video signals into digital signals.
37. What is the respective function of each connector of the capture card of the digital video recorder?
A: Lotus petals: the input interface of video (RCA)
B: S----the input interface of video
C: +5V or +12V output interface
38. What are the main functions of the audio-visual controller in the surveillance system?
A: Collect video signals.
B: Receive and distribute audio signals.
C: The long-distance transmission module of the built-in modem.
D: The remote access connection.
39. What are the name and function of the connector of the audio-visual controller?
A: BNC ( eight lines video input).
B: BNC (local output) is used for the output of local video.
C: BNC (local extended input) is used for the visual-audio controller (output from the video of the device)
D: Type D-15 holes (used for connecting the mainframe of the monitor) is a digital audio frequency line.
E: Type D-9 needles (digital line)
40. What are the name and functions of the input and output line of the audio-visual controller in the system?
A: Type D-15 cores lines communicate with the mainframe controller.
B: Type D-9 needles communicate with the computer.