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PoE and PoE +

Power over Ethernet, or PoE, distributes power and data safely over an Ethernet cable to a targeted device (or network of devices). It’s often used where universal serial buses (USB) are unsustainable and ac power is inconvenient, expensive or infeasible to supply (think wireless LAN access points, IP phones, surveillance cameras).

An added perk of PoE is that it gets powered over longer runs of cable than what the USB permits. Also, it doesn’t have to deal with the major topology and cable limitations that USB and power lines are faced with.

PoE has been in use for a while now, but as businesses have continued to invest in their data network infrastructure over the years, the need for higher power PoE systems became a growing demand. Devices like VoIP phones, WLAN access points, Web cameras and security cameras with pan, tilt and zoom capabilities are good examples of new devices that needed more power. The result of this need – PoE+.

Before comparing the two, it should be noted that the networking industry, IEEE, holds power delivery systems to a set of standards in order to reduce energy consumption and keep everyone in check. As such, both PoE and PoE+ fall under two separate standards:

TypeStandardMaximum Wattage
PoEIEEE802.3AF15.4 Wdc
PoE+IEEE802.3AT25.5 Wdc
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2MP Color 3.6mm ePoE Bullet with Night Color Technology

Model Number: DH-IPC-HFW4239TN-ASE
Series: 2MP, Bullet, ePoE, Night Color

The Dahua camera with Night Color Technology offers 24-hour color surveillance in applications with at least 1 lux of ambient light. The Night Color Technology camera utilizes back-illuminated pixel technology, a large aperture lens, and a STARVIS™ sensor to deliver color details without the need for external IR or white-light illumination. This camera is ideal for monitoring casino floors, parking lots, building exteriors and interiors, educational facilities, and urban streets. The IP67 and the IK10 ratings ensure continuous operation in the harshest environments.

Dahua’s innovative ePoE technology offers a plug-and-play solution to transmit power and data over long distances via Ethernet or coaxial cables, reducing installation time and saving money. ePoE technology is a viable, cost-effective solution for extending transmission distances and for converting existing, coax-based analog systems into IP systems. For video security and surveillance installers, ePoE technology saves time and money by reducing overall cabling requirements, allowing for existing coax cable to be used, and minimizing the number of peripheral devices needed. For new installations, ePoE offers the ability to design long-distance applications without the need for additional repeaters.

What is a NVR?

A network video recorder (NVR) is a specialized computer system that includes a software program that records video in a digital format to a disk drive, USB flash drive, SD memory card or other mass storage device. An NVR contains no dedicated video capture hardware. However, the software is typically run on a dedicated device, usually with an embedded operating system. Alternatively, to help support increased functionality and serviceability, standard operating systems are used with standard processors and video management software. An NVR is typically deployed in an IP video surveillance system.

A good NVR would allow you to issue your IP cameras there own IP address, as on my NVR my LAN/WAN address would be in the 192.168.x.x and my IP cameras could have there own addresses for instance 10.x.x.x or 172.x.x.x.

How to choose a lens for your security camera

The first specification to consider when choosing a camera lens is what is it you are trying to see. Is it and area or an object (faces, car, entry door ect.).

Focal length and field of vision

The first specification to consider when choosing a camera lens is what is it you are trying to see. Is it and area or an object (faces, car, entry door ect.).

Then its focal length. The focal length of a lens determines both the range and distance of its field of vision. The basic rule to remember is that a smaller focal length will lead to a wider viewable range. Conversely, a larger focal length will have a more narrow field of vision, but it will also have a further range. A 2.8mm lens would be ideal for capturing images in a wide field within 20 feet or so, but a 12mm lens could grab a clearer image of an object farther away. A lens with a focal length around 8mm would split the difference between the two extremes.

Like security cameras, lenses come in many different varieties. When choosing a lens, it’s important to realize what its intended function is and what limitations it may not be able to overcome. Different surveillance conditions call for a different camera and lens. An informed shopper should know what lens is best suited for his or her needs before making a purchase.

The key difference between analog CCTV and IP Cameras

Analog cameras transfer the video signals in analog form (electrical signals), usually use coaxial cables for the cabling

  • Analog cameras transfer the video signals in analog form (electrical signals), usually use coaxial cables for the cabling, and have the videos recorded by a DVR (Digital Video Recorder), where each single camera is directly connected to the DVR.
  • IP cameras encode the video signal into IP packets, use the data network (LAN) for the cabling, and have the videos recorded by an NVR (Network Video Recorder) that can be connected anywhere on the network.

Both type of cameras use the same mechanism for capturing the video by their CCD sensor, and the main difference is the method by which the video signal is transmitted.