CCTV CCTV System Components 2 — Questions and Answers
Question 1: What is the primary function of a Digital Video Recorder (DVR) in a CCTV system?
- Transmit video signals wirelessly
- Convert and store analog camera footage as digital video (Correct answer)
- Boost camera signal strength over long cable runs
- Control pan-tilt-zoom camera movement
Correct answer: Convert and store analog camera footage as digital video
A DVR converts analog video signals from cameras into digital format and stores them on a hard drive for later retrieval.
Question 2: Which connector type is most commonly used to connect coaxial cables to analog CCTV cameras?
- RJ-45
- BNC (Correct answer)
- HDMI
- XLR
Correct answer: BNC
BNC (Bayonet Neill-Concelman) connectors are the industry standard for connecting coaxial cables to analog CCTV cameras and DVRs.
Question 3: A Network Video Recorder (NVR) differs from a DVR primarily because it:
- Uses coaxial cable to receive video
- Processes video compression internally using a chip
- Receives pre-encoded digital video streams over a network (Correct answer)
- Only supports black-and-white cameras
Correct answer: Receives pre-encoded digital video streams over a network
An NVR receives already-encoded digital video from IP cameras over an Ethernet network, whereas a DVR encodes incoming analog signals itself.
Question 4: What does the term 'varifocal lens' mean in the context of CCTV cameras?
- The lens automatically adjusts focus based on motion detection
- The focal length can be manually adjusted while maintaining focus (Correct answer)
- The lens is fixed and cannot be changed
- The lens rotates 360 degrees continuously
Correct answer: The focal length can be manually adjusted while maintaining focus
A varifocal lens allows the operator to manually adjust the focal length (zoom level) and then refocus, providing flexibility for different fields of view.
Question 5: Which type of CCTV housing is rated for outdoor use and protects against weather, dust, and moisture?
- IP20-rated enclosure
- IP66-rated enclosure (Correct answer)
- NEMA 1 enclosure
- UL94 V-0 housing
Correct answer: IP66-rated enclosure
An IP66-rated enclosure is dust-tight and protected against powerful water jets, making it suitable for outdoor CCTV installations.
Question 6: In a CCTV system, what is the purpose of a video multiplexer?
- Increase the resolution of individual camera feeds
- Display and record multiple camera feeds on a single recording device simultaneously (Correct answer)
- Convert digital IP signals to analog coaxial signals
- Filter out infrared light from camera images
Correct answer: Display and record multiple camera feeds on a single recording device simultaneously
A video multiplexer combines multiple camera inputs so they can all be displayed and recorded simultaneously on a single monitor or recording device.
Question 7: What is the function of a PoE (Power over Ethernet) switch in an IP camera CCTV system?
- Encrypt video data before transmission
- Supply both data connectivity and electrical power through a single Ethernet cable to IP cameras (Correct answer)
- Convert analog video to digital format
- Manage PTZ camera presets and tours
Correct answer: Supply both data connectivity and electrical power through a single Ethernet cable to IP cameras
A PoE switch delivers both network data and DC power to IP cameras over a single Cat5e/Cat6 Ethernet cable, eliminating the need for separate power supplies.
CCTV CCTV System Components 2
What is the primary function of a Digital Video Recorder (DVR) in a CCTV system?