There are three ways of power supplying in surveillance system, including point to point, centralized power supply and power over Ethernet.
a. Point to Point
The deployment of point to point mode is that, connect the camera to a separate DC12/24V power adapter which is connected with a cable conducting AC 220V generated from monitoring room.
- Easy to maintenance and replacement. When the camera breaks down, users can quickly troubleshoot and repair or replace the equipment.
- Long transmission distance for power. The 220V strong power output can be cascaded, which can reach the long distance transmission for the power and less power losses.
- High cost. The cost of deploying multiple independently power adapters is higher than centralized power supply with the same power output.
- Weak performance of safety and stability. Strong electricity is more dangerous than weak electricity, the aging of the line and rat damage can easily lead to short circuit or even fire. Moreover, the distance between the independent power adapter and the camera is mostly in the outdoor environment, which is vulnerable to the impact of external factors such as lightning strikes.
b. Centralized power supply
The deployment of centralized power supply is to connect several cameras to a 12/24V 4A power adapter though red and black power cord/combination cable, which is connected with the 220V power source.
- Low cost.
- Simple maintenance: adopt centralized power supply mode, convenient line laying, convenient construction and management.
- The early period of deployment is complicated, it needs to decrease power losses and choose a proper cables when deploying.
- If there isn’t UPS power supply used, the system of centralized power supply would fail to work and breakdown.
c. Power over Ethernet (PoE)
PoE describes any of several standard or ad-hoc systems which pass electric power along with data on twisted pair Ethernet cabling. This allows a single cable to provide both data connection and electric power to devices such as wireless access points, IP cameras, and VoIP phones. There are two modes of PoE as following:
12/24V Passive PoE (Non-standard PoE)
- The lowest cost: only need a cable or extra PoE splitter to supply power to different devices.
- Complicated deployment, It needs to know the voltage of PD before choosing PoE switches and PoE splitters. 12V PoE switches are not recommended due to the power losses and only max 30 meters of transmission distance. While the 24 PoE switches could supply enough power to 15W PD over hundreds of meters.- Poor performance of safety and stability. There are a lot of brands of 12V/24V PoE switches with the uncertified power adapters, and without the anti-surge function on port.
Aiming at solving the above problems, UTEPO has recently launched a highly reliable 24V PoE switch. The whole series of products adopt CE & FCC certified power supply, and all ports of the switch support 6KV lightning protection and three mode dial switch control. Equipped with the 24V to 12V PoE splitter of UTEPO, it can truly solve the problems of complex deployment and high electricity cost of non-poe camera, access control, bridge and other front-end equipment.
Standard PoE (44-57V)
- Safety and Strong compatibility. With PSE chip, it only supplies power to the standard device. Non-standard PD devices such as PC, switch and NVR can also be connected freely without burning the device. It supports both IEEE802.3af/at, plug and play.
- It needs to add PD chip to front-end devices and PSE chips to switches. The cost is higher than other ways.
- As long as the on-site strong current is already set, and in order to meet the demand of convenient electricity-taking and low cost, it is suitable to solve the data transfer and power supplying through point to point method or centralized power supply.
- If the front-end devices is non-standard PoE devices, the deployment of strong current is troublesome and costly. Therefore, it is better to select 24V PoE switch with corresponding PoE splitter, which is the most cost-effective choice to solve the data transmission and power supply problems of the front-end equipment.
- If the front-end devices is standard PoE devices, the deployment of strong current is troublesome and costly. Therefore, it is better to select 44-57V PoE switch, which is the most cost-effective choice to solve the data transmission and power supply problems of the front-end equipment.
More and more PoE equipment shown in mid-large size security exhibitions which revealed the technology of PoE power supply is poised for market. However, PoE is not the main stream because of the following reasons：
1. Price difference of camera with or without POE that produced by industry magnates.
2. High cost of PoE switch with different quality standard.
3. People would like rather to use independent power-supply device or centralized power supply to replace the PoE device because of its low heat-dissipation, big self-consuming, and poor anti-surge function.
But we trust as long as the cost of PoE drops down, more and more factories will present cost-effective poe network power supply. Moreover, as the labor cost of engineering industry is increasing day by day. The engineering contractors will gradually realize the application value of POE splitter and PoE power supply switch, finally PoE power supply technology will be leading security and monitoring industry.