Cabling for security and surveillance systems involves a wide range of considerations. Different systems and applications have different functional and installation requirements, which means that the appropriate cable types and specifications may vary accordingly.

The following six guidelines outline the key cabling considerations for security and surveillance system installations, including video transmission, power supply, PTZ camera control, alarm and audio monitoring, broadcast and intercom systems, and computer networks.

1. Video Transmission Cables for Surveillance Cameras

For surveillance camera video transmission, 75-ohm coaxial cable is commonly used. However, the attenuation of video signals varies depending on the cable diameter. In general, the larger the cable diameter, the lower the signal attenuation, making thicker coaxial cables more suitable for long-distance transmission.

The appropriate cable should be selected according to the required transmission distance and cable specifications. Typical recommendations include:

• Up to 300 m: SYV-75-3
• Up to 500 m: SYV-75-5
• Up to 800 m: SYV-75-7 or SYV-75-9
• Up to 1,000 m: SYV-75-12

For longer transmission distances, a larger-diameter coaxial cable is generally recommended to minimize signal loss.

2. Power Cables for Surveillance Cameras

The power supply for a video surveillance system should generally be wired separately from other system circuits. A main power switch can be installed in the monitoring room, with a UPS (Uninterruptible Power Supply) providing backup power and centralized control for the surveillance system.

In typical installations, AC 220 V power is supplied to the camera location and converted to DC 12 V through a power adapter.

However, camera power requirements vary by model. Some cameras may require 5 V, 12 V, or 24 V DC power. The cable type, power supply configuration, and installation method should therefore be selected according to the specifications of the individual camera.

3. Cabling for PTZ Cameras and Motorized Lenses

Cameras equipped with motorized pan-tilt units (PTZ) or motorized lenses require additional control cabling in addition to the video and power cables described above.

Communication cables are required between the field decoder/controller and the central control system. Common options include:

• 2-core shielded communication cable (RVVP)
• Category 3 twisted-pair cable (UTP)

The recommended conductor cross-sectional area is approximately 0.3–0.5 mm² per core, depending on the system requirements and transmission distance.

4. Alarm and Audio Monitoring Cables

For alarm systems and audio monitoring in areas such as monitoring rooms, corridors, and other controlled areas, shielded communication cables are commonly used to help reduce electromagnetic interference and maintain signal quality.

Typical cable options include:

• 4-core shielded communication cable (RVVP)
• Category 3 twisted-pair cable (UTP)

A conductor cross-sectional area of approximately 0.5 mm² per core is commonly used, subject to the specific system requirements.

5. Broadcast and Intercom Cables

For broadcast and intercom systems installed in areas such as corridors, facilities, and industrial sites, cable selection should take the transmission distance into consideration.

As a general principle:

The longer the transmission distance, the larger the cable size required.

For RS-485 communication, the standard maximum communication distance is typically 1,200 m under recommended conditions. In practical installations, RVV-2/1.5 sheathed cable may be used to extend the communication distance to approximately 2,000 m, depending on the system configuration and installation conditions.

For broadcast and intercom applications, the appropriate cable type should be selected based on the required transmission distance and system specifications. Twisted-pair cables may also be used where appropriate.

6. Computer Network Cabling

Computer network cabling can generally be divided into two main categories:

Vertical backbone cabling is used for building risers and inter-building connections. Fiber-optic cable is typically preferred for these applications because of its high bandwidth and long-distance transmission capabilities.

Horizontal cabling is used to connect work areas to telecommunications or equipment rooms. Four-pair, eight-core Category 5e shielded twisted-pair cable is commonly used for these connections.

For inter-building connections, 50/125 μm fiber-optic cable may be used. Depending on the network architecture and transmission requirements, either multimode fiber or single-mode fiber can be selected.

For connections between work areas and telecommunications rooms, 4-pair/8-core Category 5e shielded twisted-pair cable is commonly used.

Conclusion

These six guidelines cover the key cabling considerations for security and surveillance system installations, from video transmission and power supply to PTZ control, alarm monitoring, broadcast and intercom systems, and network infrastructure.

Proper cable selection should always take into account transmission distance, signal attenuation, power requirements, environmental conditions, and system specifications. Selecting the appropriate cable and following proper installation practices can help ensure reliable system performance and long-term operational stability.

※ Cable specifications and installation requirements may vary depending on the equipment manufacturer, system design, local electrical codes, and project conditions. Always refer to the applicable technical standards and manufacturer specifications before installation.