POE(Power over Ethernet) Definition

POE is a technology that enables the transmission of data and power over Ethernet cables (Cat5, Cat5e, Cat6, etc.). The POE standard defines the power supply equipment (PSE) and the powered device (PD). The PSE is usually a POE switch or a POE injector, and the PD is a device that needs power such as an IP camera, wireless access point, etc.

POE standard

-IEEE 802.3af: Provides a maximum of 15.4W of power, and the actual power delivered to the device is about 12.95W, which is suitable for devices with lower power requirements.

-IEEE 802.3at (POE+): Provides a maximum of 25.5W of power, and the actual power delivered to the device is about 21.9W, which is suitable for devices with higher power requirements.

POE advantages

1. Simplified wiring: Only one Ethernet cable is required to achieve data and power transmission, reducing wiring complexity and cost.
2. Flexibility: Allows remote devices to be installed in places where it is difficult to access power, improving the flexibility of equipment layout.
3. Centralized management: Power supply equipment can be centrally managed and monitored through POE switches, which is convenient for maintenance.
4. High safety: POE equipment has functions such as overload protection and short circuit protection to ensure the safety of equipment and personnel.

Disadvantages of POE

1. Distance limitation: The transmission distance of standard Ethernet cable generally does not exceed 100 meters. A repeater or POE extender is required for distances exceeding this distance.
2. Power limitation: POE has limited power supply capacity and is not suitable for high-power equipment.

Actual example

For example, to install an IP surveillance system, only one Ethernet cable needs to be laid at each camera location, and power supply and data transmission are carried out through a POE switch, which simplifies construction and maintenance.

POC (Power over Coaxial) Definition

POC is a technology that transmits power and video signals simultaneously through coaxial cables (such as RG59, RG6, etc.). While transmitting video signals, coaxial cables can transmit DC current to supply terminal devices such as cameras. POC technology is usually used in analog camera systems or to transform old coaxial cable systems to support new camera equipment.

Advantages of POC

1. Utilize existing wiring: The existing coaxial cable network can be used without rewiring, saving cost and time.
2. Long-distance transmission: Coaxial cable can achieve longer distance transmission, usually up to 300 meters or even farther, suitable for large-scale monitoring systems.
3. High bandwidth: Coaxial cable has high bandwidth capacity and can support high-definition video transmission.

Disadvantages of POC

1. Poor flexibility: Coaxial cable is thicker and not easy to bend, and the wiring flexibility is not as good as Ethernet cable.
2. Equipment compatibility issues: POC is mainly used for specific brands and models of equipment, and there may be compatibility issues.
3. High wiring complexity: The connectors of coaxial cables (such as BNC connectors) are relatively complex, and wiring and maintenance are difficult.

Actual example

For an old analog monitoring system, when upgrading to a high-definition digital system, the use of POC technology can use the original coaxial cable to achieve high-definition monitoring upgrades without changing the wiring.

Comparison of POE and POC

POE and POC each have their own unique advantages and applicable scenarios. POE is suitable for new networks and occasions that require flexible wiring, while POC is an ideal choice when it is necessary to upgrade the old coaxial cable system. The specific choice of which technology should be based on a comprehensive consideration of multiple factors such as actual needs, wiring environment, and device compatibility.

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