Info Powering cameras via PoE. Video surveillance over twisted pair Wiring of twisted pair for IP cameras
Prehistory
I myself am far from video surveillance systems, but after building the house I decided to try it. First I bought an analog video recorder because... a couple of free cameras were available. It sat there for 2 years, but they never got around to pulling it out and connecting it. And then I came across cheap IP cameras at an Aliexpress sale, and there were still coupons left, so I decided to try them out. But because My own home is a lot of constant work around the house and grounds, so they stayed with me for another six months. In the summer, when the weather is good, I decided to install it. First I placed it inside the house with observation through the glass window. During the day it’s fine, at night there’s only glare from the house lighting. I decided to move it outside the window. Holes with pipes to the street were previously made during the construction phase. But the diameter of the tube was 20 mm, it was problematic to insert the network and power connectors into it, and along the length they ended up inside the tube. It was decided to do PoE power supply. The option is simple - buy PoE injectors and install them at home and outside the window. Hanging a box by the window to place a PoE injector seemed not comme il faut; placing it inside the base of the camera was also not possible. A more complicated option is to cut off the connectors, solder a network cable with RJ45, insert it through the tube into the house, and make an RJ45 socket with a PoE injector. But the lunar cycles and the positions of the planets were such that I burned the camera board. More precisely, the network interface. The camera itself seemed to be working, judging by the clicks of the IR filter. It was decided to buy a new board with a camera module. Having scoured the expanses of Aliexpress, it turned out that the difference in the price of the HD and FullHD module is 300-400 rubles. Well, let's go for a walk, let's take FullHD.
The module is designed for installation in surveillance cameras to replace/upgrade standard modules.
- CHARACTERISTICS
- Resolution: 1080P (FullHD)
- Processor and matrix model: 2035+3516C
- Sensor type: CMOS
- Minimum illumination lux: 1 LUX
- Video compression format: H.264
- Matrix resolution: 2.0MP 1080*1920
- Supply voltage:12V
- PCB dimensions:38*38mm
Inside, a cell of foam material was wrapped in a bubble wrap. The kit included a small cable to connect the light sensor to the module.
Cable included
The sensor itself on the camera is covered with a protective film. For scale there is an adapter for SD format.
Sensor packaging
Compared to the previous module, the sensor area is slightly larger, which may indirectly indicate better light sensitivity.
Sensor comparison
Installation in the camera did not cause any problems; when purchasing, I chose a board with the same connectors. In general, there are different network connectors and pinouts. In addition, in the cameras that I had, the power connectors (circled in the photo) on the IR illumination board were located oppositely, i.e. if you take the backlight board from one camera and put it in another, then “+” will go to “-”, and “-” to “+”. Whatever I immediately noticed, it’s good that nothing burned out, the backlight and light sensor just didn’t work.
Installation in camera
Let's take our camera 
Unscrew the cap, normal right-hand thread. Unscrew the 4 screws securing the board to the cover. The module is pulled out with the IR illumination board, remove this board. It turns out like this 
View from the connectors 
We rearrange the connectors from the old module to the new one.
Next is the moment of truth. Having replaced the board, without the lens for now, I immediately decided to check whether this module worked at all.
Checked from CMS
Enter the standard IP 192.168.1.10 and port 34567. 
Voila, the camera works, but it only shows a zebra without a lens and with film. 
Now you need to rearrange the lens with the IR filter. I didn’t take pictures because... The workshop was dusty, and it was necessary to quickly rearrange it so that as little dust as possible would get in.
There's nothing complicated there. We disconnect the IR filter connector, unscrew the 2 lens mounting bolts from the old module, remove the protective film from the new module, attach the lens to the new module with 2 bolts and connect the connector.
2 mounting bolts
All that remains is to adjust the focus and assemble the camera. To adjust the focus, connect the camera, unscrew the fixing screw and rotate the lens to adjust the focus. Then tighten the fixing screw.
fixing screw
After adjusting the focus, it takes pictures quite tolerably. The web interface works, but as expected from cheap Chinese cameras, only in IE.
It is used to power IP surveillance cameras, IP telephony, WLAN wireless networks and other network devices.
Thus, one cable is capable of transmitting information traffic and providing power to the device.
PoE was described by the IEEE in 2003 with the IEEE 802.3af standard.
The new IEEE 802.3at standard appeared in 2009 and is called by many as PoE+.
Devices with PoE and PoE+ are active. This means that the PoE source matches the PoE consumer and is intelligent.
Unlike PoE, many manufacturers use (usually for their equipment) so-called Passive PoE. This means that such a PoE source does not poll the consumer and does not negotiate power.
Their advantage is their low cost.
Disadvantage - incompatible source and consumer can negatively affect the operation of the system as a whole (from inoperability to short circuit).
As a result, PoE currently exists in several versions:
- according to the 802.3af standard,
- according to the 802.3at standard,
- according to proprietary private standards, of which Passive PoE is the most famous.
IEEE 802.3af, 802.3at standards - active PoE
The main advantage of PoE sources that support these standards is their intelligent operation.It allows you to avoid equipment damage, extend its service life, and save energy consumption.
Connecting a powered device occurs in several stages:
- Before applying operating voltage to the network device, the supply side checks the connection. A voltage of 2.8 to 10 volts is applied to the device and the input resistance is determined, which should be in the range from 19 to 26.5 kOhm.
- Next, the device is classified by power consumption depending on the class. If the device begins to consume a current greater than that provided for this class, the power will be turned off.
- Then full voltage is applied to the device, however, at this stage, consumer control occurs. If a network device consumes less than 5 mA of current for 400 ms, the power will be turned off. If a current of more than 400 mA flows to the powered device for 75 ms, the power will also be turned off.
Differences between PoE and PoE+
5 PoE power classes defined by IEEE 802.3 standard
| Class | Standard | Mode | Usage | Current classification, mA |
Power per port, W |
Power per device, W |
|---|---|---|---|---|---|---|
| 0 | 802.3af/802.3at | Basic | Default | 0-4 | 15,4 | 0,44 - 12,95 |
| 1 | 802.3af/802.3at | Optional | Optional | 9-12 | 4,5 | 0,44 - 3,84 |
| 2 | 802.3af/802.3at | Optional | Optional | 17-20 | 7 | 3,84 - 6,49 |
| 3 | 802.3af/802.3at | Optional | Optional | 26-30 | 15,4 | 6,49 - 12,95 |
| 4 | 802.3at | Reserved | Only 802.3at (Type 2) devices are allowed | 36-44 | 30 | 12,95 - 25,5 |
Operating principle of PoE devices
- use of free pairs for power (in Ethernet 100BASE-TX networks)
- simultaneous transmission of power and data over one signal wire (method A)
- transfer of power and data according to the principle “data - potential difference in a pair of wires”; “power - potential difference between pairs of wires” (method B)
Method A
Both electricity and data are supplied through wires 1, 2, 3, 6.Cores 5, 7, 8 are not used.
Method B
Cores 4, 5, 7, 8 are used to supply power.The data is transmitted to the rest.
802.3af PoE-A and PoE-B standards for 100 and 1000 Mbps networks.
Pinout of 8-pin 8P8C (RJ45) connector
| PINS on Switch | 10/100 Mb/sec DC on Spares (Method B) |
10/100 Mb/sec Mixed DC & Data (Method A) |
1000 Mb/s DC & Bi-Data (Method B) |
1000 Mb/s DC & Bi-Data (Method A) |
| Pin 1 | Rx+ | Rx+DC+ | TxRx A+ | TxRx A+DC+ |
| Pin 2 | Rx- | Rx - DC + | TxRx A - | TxRx A - DC + |
| Pin 3 | Tx+ | Tx + DC - | TxRxB+ | TxRx B+DC - |
| Pin 4 | DC+ | not used | TxRx C+DC+ | TxRxC+ |
| Pin 5 | DC+ | not used | TxRx C - DC + | TxRx C- |
| Pin 6 | Tx- | Tx - DC - | TxRx B - | TxRx B - DC - |
| Pin 7 | DC- | not used | TxRx D+DC - | TxRxD+ |
| Pin 8 | DC- | not used | TxRx D - DC - | TxRx D- |
PoE cable
The quality of the cable directly determines the quality of PoE and the distance over which it can be carried.The twisted pair must be selected:
- four-pair, not lower than cat.5e, copper, not copper-plated (not bimetal),
- with a conductor thickness of at least 0.51 mm (24 AWG),
- with conductor resistance not higher than 9.38 Ohm/100 m (higher values contribute to greater power loss in the cable),
- good manufacturer.
Passive PoE is effective for use in existing network infrastructure, allowing PoE technology to be used for devices that are not equipped with this function natively.
The PPoE kit does not include any power supply unit (PSU), since it is assumed that in most cases you can use the standard PSU included with the device.
PPoE provides power supply over standard twisted pair cable to remote devices such as wireless access points, IP phones, IP cameras, etc.
Power is supplied in the same way as in classic PoE over free twisted pairs 4-5 and 7-8, which are not used for data transmission.
The maximum cable length when using a Passive PoE injector is significantly less than when using a PoE injector (10-20 meters).
Of course, the main purpose is to guarantee the safety of a specific room, place or object. However, malfunctions or breakdowns in the power units, even not as significant as it seems, lead to the fact that an initially reliable and high-quality video surveillance system becomes absolutely useless, since it does not receive power.
CCTV camera power supply
The most suitable way to create a high-quality video monitoring system is to use modern high-resolution cameras. Such devices are distinguished by good image clarity and high reliability during operation. However, the need for significant current forces owners of such systems to responsibly and clearly organize the electrical power supply of digital video cameras.
As you know, video surveillance can be either inside a certain space or outside it. The power supply system for these cameras is similarly different:
- in rooms where heating is created, the need for power exists only directly at the IP cameras themselves;
- external circuits require night lighting and heating, so they need to create conditions for increased power.
PoE power supply for IP cameras
Thanks to the advent of Power-over-Ethernet technology, abbreviated PoE, it became possible to supply power to video surveillance cameras, access points and IP telephony. As is known, such devices have a negative attitude towards wiring a separate cable nearby for power supply, so the use of PoE technologies made it possible to eliminate the impact of extraneous interference on the signal quality.
An additional benefit of delivering power and information through the same cable is reduced installation costs and reduced installation time. After all, when creating a system you do not need to use a large number of cables.
Unfortunately, the Power-over-Ethernet system also has its disadvantages:
- The IP camera that needs to be powered must necessarily support the specified technology;
- The size of the cable through which the power is supplied has limitations - its maximum size should be up to one hundred meters.
When choosing the cable to be used for the system, you need to take into account its quality and the length of the twisted pair. It is best to purchase products from reliable manufacturers; select twisted pair cables made entirely of copper, not coated with copper. Conductors must have a minimum thickness of 0.51 mm.
Power over twisted pair
Due to the fact that the length of the Ethernet cable is limited to one hundred meters, professionals have proposed other possible solutions, the implementation of which will require additional equipment:
- Using converters. These devices operate using VDSL2 technology, allowing the transmission of information from IP cameras while simultaneously supplying power via twisted pair cable. If the video surveillance system uses relatively low power, this method helps power the system over a distance of up to one and a half kilometers.
- Use of repeaters. In this case, special PoE repeaters are used (translated from English as “repeaters”). Such devices allow you to receive information streams and power supplies, and then transmit them via an Ethernet wire to another device.
- Repeater chains. If you add several repeaters to the system at once, you can increase the distance from the power source to the video surveillance camera several times.
Pinout of IP camera over twisted pair
In order for a CCTV camera to support PoE technology, this compliance must be ensured. This is done in several stages.
- The first step is to check the power supply. The device connected to the system must be supplied with a voltage of 2.8 to 10 Volts. Then you can calculate the resistance of the connected device at the input. If you meet the requirements, you can proceed to the second step.
- The device that provides power helps determine how much power the connected device consumes. This is necessary in order to be able to subsequently manage this value. Depending on the results obtained during the calculation process, that is, how many watts the video surveillance camera consumes, the device is assigned one of five classes: from zero to four.
- The next stage is supplying a voltage of 48 Volts with a maximum increase of 400 ms, and monitoring the operating state of the IP camera, that is, the power supply ends in cases where:
- more than 400 mA of current is supplied for 75 ms;
- less than 5 mA of current is supplied for 400 ms;
- The resistance of the video surveillance camera will reach parameters greater than 1980 kOhm within 400 ms.
There are two known standards for Power-over-Ethernet technology. In this case, video cameras for surveillance systems, as well as access points and IP telephony are connected using the IEEE 802.3af standard. PoE technology according to this standard allows you to provide up to 25.5 Watts of power. Some manufacturers' products can provide up to 51 watts of power per cable.
Pinout is carried out according to the following scenario:
| Pin | Alternative | Second way |
| First | Vport + | |
| Second | Vport + | |
| Third | Vport — | |
| Fourth | Vport + | |
| Fifth | Vport + | |
| Sixth | Vport — | |
| Seventh | Vport — | |
| Eighth | Vport — |
In order for a device to be connected in this manner, it must meet the power requirements:
- peak input current – 400 mA;
- voltage cut-off – at 30 Volts;
- voltage switching on – at 44 Volts;
- input voltage is supplied in the range from 36 to 57 Volts;
- maximum power consumption – up to 12.95 Watts;
- resistance range – from 23.75 to 26.25 kOhm;
- The maximum start time for more than 10 mA is 300 ms.
Pinout can also be carried out according to the third type. When using this option, all cable cores are used in four pairs, which provide power supply. However, this pinout method can be found not so often, since it is used only in the implementation of PoE technology by manufacturers. An example is the use of UPOE technology in Cisco brand devices.
If the equipment elements used on the same network support one of the standards - 802.3at or 802.3af - then the pinout method can be ignored. It can be neglected due to the fact that the device that consumes power via PoE, after installation, will be able to work with both the standard and the other. However, the type of pinout will be important when standards vary.
Power supplies
A competent approach to choosing a specific power supply will ensure long-term and reliable operation of the video surveillance system and IP cameras in particular. If the power supply does not match the parameters of the video camera or turns out to be of low quality, the camera may fail or become completely unsuitable for further use.
The power supply, which must be designed for a video surveillance camera, must provide exactly the parameters required by the technical instructions of the IP device, and also meet the following requirements:
- protection against possible overloads or short circuits;
- the ability to operate the system in continuous mode;
- stable work.
The organization of power supply over twisted pair makes the organization of supply redundancy as simplified as possible than when operating analog devices. In this case, you can limit yourself to using an uninterruptible unit for a special switch operating using PoE technology. In this case, all IP cameras will be connected to this switch. The use of such a scheme helps to organize high-quality power supply without interruptions.
When purchasing a power supply, you should not choose the cheapest options, since only a high-quality device is guaranteed to meet safety requirements and avoid serious problems such as fire or combustion. It is recommended to make purchases at trusted retail outlets that sell equipment at a professional level.
Any user has recently had the information firmly stuck in his head that IP video cameras are much better than analog ones. This article will discuss the principle of connecting both IP and analog models.
After all, only a few years ago analogue high-definition cameras appeared. These are AHD, CVI and TVI formats. In terms of resolution and picture quality, they are practically not inferior to the IP format, and the cost is several times cheaper.
As a rule, these are 1 or 2 Megapixel cameras. Their price segment is from 1000 to 2500 rubles. Moreover, if you already have an analog system installed and you just want to expand the number of cameras, or replace burned out ones, now it’s enough to buy modern inexpensive models with an OSD menu. 
They have a switch on the shank that allows you to switch them to analog PAL mode.
Installation of video surveillance with analog cameras
Before you directly install video surveillance in your home, you need to draw on paper the locations of video points, cable laying locations, etc. 
In order to maximize coverage of the entire space around the house, it is necessary to install at least one camera on each wall. It wouldn’t hurt to put another one on the roof in front of the front door.
Video surveillance materials
Here are all the materials you will need to install an analog video surveillance system:
- cable for powering the entire system from a 220V network
It is best to use the VVGnG-Ls 3*1.5mm2 brand. 
- wires for switching in low-current switchboard - PUGV 1.5mm2
Do not confuse with KVK-V. The KVK-P brand is an outdoor option, and KVK-V is for installation inside the house. It is not UV protected. 
- 3-core PVA wire cross-section 1.5mm2
First check that the number of video inputs on it is equal to or greater than the number of cameras.
- computer hard drive for video storage and recording
The minimum recommended volume is 1TB. You can use both large 3.5-inch and small 2.5-inch disks. Small drives are much quieter and generate less heat. 
- power unit
For example, the same as is used to connect LED strips. A standard power supply with a cable cross-section of 0.75 mm2 is enough for high-quality signal transmission over a distance of no more than 500 m. 
Select the power of the unit according to the same principle as for LED strips. That is, the total power of all cameras + 30%.
They are needed to connect the cable to the camera itself and connect to the video input of the recorder.
If you don't want all your video surveillance to burn out in the first thunderstorm, don't skimp on this piece of protection.
It is most convenient to connect a DVR or UPS via a plug and socket. Please note that all these materials must be compatible with each other. Simple IP equipment will not work with analog equipment and vice versa.
You can choose ready-made video surveillance kits, or individual components - cameras, video recorders, cables, connectors, plus you can get acquainted with the current prices today.
220V power connection in the low current cabinet
The low-current switchboard, where the DVR, power supply, etc. are located, may be located in a different room from the general 220V switchboard, sometimes even in the garage or basement.
Therefore, the first thing you need to do is supply electricity there.
Ditch the walls and lay the VVGnG-Ls 3*1.5mm2 cable from the 220V switchboard to the low-current cabinet. You power it from a separate modular circuit breaker with a rated current of 10A. 
In a low-current panel, connect the power cable to the terminals of another circuit breaker. It will be an introductory one for this cabinet. And directly from it you connect modular sockets and a surge arrester. 
The arrester is connected according to the diagram below. The white and brown wire is the phase, the blue wire is the neutral wire, and the yellow-green wire is the ground wire. 
Connecting sockets: 
In the same cabinet there are:
- power unit
- DVR + 1TB disk
- UPS
The hard drive is mounted in the recorder itself. To do this, unscrew the screws and disassemble it. There should be a space inside for the hard drive. 
Connect the connectors, and then screw the drive into place.
Please note that often the DVR case is also a cooling radiator for the disk.
Next, you power the UPS from the sockets through a regular plug. Most power supplies come without wires with a plug included, so here you will have to do it yourself. Use PVS wires and a regular Euro plug. 
Mount a plug on one end of the wire, strip the other and connect it to the unit at the 220V power terminals, designated L and N. 
There is no particular difference in phasing or polarity where to connect zero and phase. Next, connect power to the video cameras. 
If there are not enough 12V output terminals on the unit, it is best to use terminal blocks. Set them according to the number of cameras and label the pins as “+V” and “-V”. 
Then, using PuGV wires, connect the 12V +V and -V output terminals from the power supply, with the corresponding connectors on the first terminal block. 
It is better to use red wires for the positive wire, and black wires for the negative wire. The remaining terminals are powered by jumpers. 
Installation and connection of cable KVK-P
Now you need to lay the KVK-P cable to each video camera, or rather to the place where you planned to place them. You can lay it indoors either in a plastic channel or simply on top of the walls.
On the street, if desired, it can be protected with corrugation, but not necessarily. 
To protect the connection points between the cable from the recorder and the cable from the camera from snow and rain, mount a junction box on the wall and route the wires into it. 
Next, remove the top layer of insulation from the cable, about 8-9 cm, and strip the two power cores. Press them with NShV tips. 
Insert these wires into the male power connector. There are two connectors "+" and "-". As we already agreed before, the red wire will be the positive contact, the black wire will be the negative one. 
After this, remove the insulation from the coaxial cable.
Carefully move the outer braid of copper back so that not a single hair has accidental contact with the core in the center. Otherwise, the quality of the picture will be poor, or there will be no picture at all.
Expose the central core by 3-4mm and mount the BNC-F connector. 
Insulate everything from above with a protective cap. 
Connect the connectors together and close the lid tightly. 
To prevent moisture from getting inside, it is necessary to use a box with sealed cable entries on the sides. 
All other video cameras on the walls of your house are connected in the same way. To each of them you will have to pull a separate KVK-P cable. 
Connecting wires on the DVR
Now all the video surveillance cables need to be disconnected in the low-current cabinet. First, connect the DVR itself via an uninterruptible power supply.
Then you strip the second ends of the KVK-P cable, brought into the cabinet, in the same way as shown above. In this case, connect the power wires (red and black) to the corresponding terminal blocks “+V” and “-V”. 
And insert the end of the coaxial cable, with the BNC-F connector installed, into the free socket of the DVR. Where it says Video In. 
Do the same with the remaining video cameras. 
All you have to do is set up the video surveillance by connecting the monitor to the recorder via VGA or HDMI connectors.
If the low-current cabinet is located far from the computer, you can use a laptop to configure it. And after that, output the signal to the monitor using a separate cable.
To safely use the monitor for other purposes, you can connect a computer to the HDMI connector, and cameras to the VGA connector. Then by changing modes you can easily switch pictures from different sources.
All software for setting up video surveillance must be included with the video cameras. If for some reason it is not there, then you can try universal software, for example from ivideon.
Connecting IP CCTV cameras with PoE
To mount and install IP cameras, in addition to the materials indicated at the beginning of the article, you will need slightly different components:
The PoE function allows you to transmit both signal and power over the same cable through one connector.
Today, I will tell you how you can connect an IP camera via twisted pair cable along with power to a computer, switch or recorder at a distance of no more than 100 meters.
Since we need only 4 wires to transmit data over twisted pair cable at a speed of 100 MB, we will use the remaining 4 for power supply, 2 wires for plus and minus.
To connect we need:
- Crimping Tools
- RJ45 plug
- twisted pair
- Plug for connecting power to a video camera 2.1 mm x 5.5 mm
- power unit
- The video camera itself.
To connect RJ45 I use a direct crimp circuit for 4 wires of an orange and green pair.
The brown and blue pair are used to connect the power. I always use the blue pair as a plus, the brown pair as a minus.
First, we remove the insulation from the twisted pair, 7-10 centimeters is enough. We separate the pairs, green and orange in one direction, blue and brown in the other.
Now comes the hardest part, putting on RJ45 according to the scheme, namely:
orange-white – 1 pin,
orange – 2 pins,
green-white – 3 pins,
green – 6 pins.
It is with pin 6 that at first there are the most problems, but with practice this procedure goes very quickly.
Having crimped the twisted pair, we proceed to connecting the power. For this purpose connectors like 2.1 mm x 5.5 mm. The plus and minus terminals are already marked on them; we simply clear the insulation from the wire there, and clamp the blue pair with bolts, respectively, to the plus, and the brown pair to the minus.
A little about the power supply and its power. According to the passport, external surveillance cameras consume a maximum of 500 milliamps, which in practice is not entirely true. I calculate the power of the power supply with a reserve, and allocate about 1 ampere to one camera. Since the cable length can be 100 meters, there are always some losses, plus voltage is also lost at the connectors. At night, the camera works with infrared illumination, which also increases the load. In the example, I connect the camera to a 12V, 5 amp power supply. Very good power supplies, very reliable, and at the same time the load can hold more than the declared 5 amperes. According to my measurements, the output was 6.5 amperes, which is not bad.
By connecting the wires to the power supply, and RJ45 to the network, testing the camera. Before connecting the camera, you can check for a break in the network cable, which I reviewed in one of the articles.
If the network is installed, the light on the network connector of the camera or switch will light up, and you can log into the camera via a computer.
Result
I will describe how the camera is set up in future articles.
Not long ago I installed this camera: 2MP IP camera. An overview of the unboxing of this camera can be found here. I really liked the quality of the shooting. I recommend.