Connecting an IP Camera over Twisted Pair

IP cameras PoE, special requirements and uninterrupted operation. putting it all together

connecting, camera, twisted, pair

Building a video surveillance system may at first glance look like a simple task.

Its implementation requires a fairly wide range of issues to be addressed. In addition to organizing data channels, collection, storage and retrieval of the necessary information you need to power the cameras, as well as management and diagnostics.

Advantages of IP camera solutions

There are quite a lot of technical means: from the traditional analog cameras to small USB web-cameras and miniature video recorders.

Sufficiently convenient and affordable solution looks the use of IP-cameras to obtain images.

This type of camera transmits images in digitized form over an IP network. It gives a number of advantages: the picture from the camera comes directly in digital form, ie does not require special converters, the information is easier to process, organize, search the archive, and so on.

If it is possible to run a network cable, and the distance between the switch and the cameras does not exceed the allowable values, the Ethernet network based on twisted pair is usually used, and the cameras working through a cable connection. Such solution provides a stable connection and practically does not depend on outside factors, such as the choice of frequency range, the presence of radio interference and other nuances.

Using a wired connection also allows you to use the same cable (twisted pair) to power the cameras. Power Over Ethernet, PoE.

PoE for video surveillance. Standards, parameters, cable crimping schemes.

Uses the potential of the Ethernet layer, i.e. conventional LAN cables.

What’s POE?

  • PoE IEEE 802.3af first generation PoE provides up to 15.4 W of power for each connected device.
  • PoE IEEE 802.3at this standard provides up to 30V for each device. So PoE can power more powerful devices such as Pan-Tilt-Zoom (PTZ) surveillance cameras and high-performance wireless 11n access points.
  • IEEE 802.3bt this technology delivers up to 51 watts over a single cable, in which case it uses all four pairs of twisted-pair LAN cable.

How PoE works? The algorithm for supplying power to a POE device.

Power is supplied only after coordination between the consuming device and the supplying device. This happens automatically in fractions of a second. Huge security advantage! For example, you took a PoE power injector and accidentally plugged the PoE output into a computer network card. The injector will check whether the network card needs power, the network card will not respond, no power will be supplied and nothing will burn out (which can not be said about passive PoE).

1) First of all a check is made: whether the connected device is powered or not. It is supplied with voltage from 2,8 to 10 V, the input impedance of the device to be connected is determined. If the parameters are as required, the power supply device proceeds to the next step.

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2) The power supply device detects the power consumption of the connected device, to control this power later.

After the device is classified, the full voltage of 48V is applied to it with a rising edge of no more than 400 ms., and the power supply device proceeds to monitor its operation:

  • If the device draws less than 5 mA for 400 ms, the power is cut off;
  • If the resistance of the connected device is greater than 1980 kohms for 400 ms, the power supply is cut off.
  • If current draw exceeds 400mA for 75ms, power is cut off.

What voltage POE supplies for IP cameras?

During device testing, 3-10V is supplied. Once the device is detected, 48V (36-57V) goes to the camera

Twisted pair POE requirements

  • Requires a four-pair twisted pair of category no lower than cat.5e (4x2x0.5);
  • Twisted pair must be copper, not copper plated;
  • The thickness of the conductors is at least 0.51 mm (24 AWG);
  • the resistance in the conductors should not be higher than 9,38 Ohm/100m (if higher, there will be a big loss of power).

802 standards.3af and 802.3at say the twisted-pair length for PoE is 100m. But in practice, the recommended maximum cable length should not exceed 75m.

How to choose twisted pair cable for your home, read here:

POE cable pinout. How to Crimp a POE Cable.

If you are installing equipment on both sides of the network that supports the 802.3af/802.3at, then the type of pinning, in fact, does not matter, because the PoE-consuming device can work with any of them. However, when it comes to combining equipment of different standards, it can be important.

Direct order of crimping a twisted pair into an RJ45 connector in the 568B circuit.

How to power IP cameras by PoE

PoE technology (Power over Ethernet) makes it possible to transmit power and data simultaneously over an Ethernet cable. Twisted pair is commonly used to power equipment when it is not technically possible or economically feasible to lay additional electrical cable. The device that is handing out PoE connects through the RJ-45 network port to the device that is consuming PoE power. In theory it’s simple, but in practice there are nuances.

First, there is smart PoE that complies with IEEE 802.3af, 802.3at, 802.3bt and there is Passive PoE without standards. The difference between PoE standard 802.3af (15 W) and PoE 802.3at (30W) in transmitted power per port. Introducing the new PoE standard 802.3bt to power high-power devices by a factor of 2 to 3 increases the power that is delivered to your end devices. up to 90W. Still worth considering. that some power is always lost in transmission: the length of the cable increases the loss.

As for Passive PoE, this is a cheaper equivalent of the 802.3af, 802.3at and 802.3bt. Passive power significantly reduces the cost of equipment. There is one thing. equipment does not check devices that need power over twisted-pair cable for power consumption and status. Voltage is applied and there is a risk of incompatibility between the equipment, which can lead to instantaneous failure or the device will fail later due to overheating and burning of the boards.

PoE power is used by many endpoint devices such as IP phones, access points. If your IP camera or IP phone supports 802.3af, then an injector (power supply) like 802.3af as well as 802.3at, 802.3bt. It will not give out more than the IP camera can take in, which means the device will not burn out.

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But if you have a camera that consumes more than 15.4 W, supporting remote directional control and zoom (PTZ IP camera), then you only need an 802 power supply.3at/802.3bt. 802.3af will not work for you.

How to connect an IP camera over twisted pair?

Have a network cable

There is a camera

What in this example do you need to connect the wires to the network wire ?

Simple 11 Комментарии и мнения владельцев

Alexander, Thank you for the reply. One more question, I connected the camera to Ethernet with this scheme

How do I set it up? Is there any wireless network available?I have a special program. Can you direct me where to find out about this.

2 IP camera Over a single cable by POE Switch | 2 IP camera over a single cable without any splitter

220V for power supply installed near the camera, if the link is more than 20-30 m). If you want to connect like in the article, you have to use a four-pair quality cable with a short distance to the camera. As for the article: judging by the photo, the author has a camera with PoE IEEE 802.3af and it is reasonable to power it from a separate PoE injector or switch with PoE power on the ports, using 48V rated power, where a few volt drop on a long wire is not critical. Of course, when installing one or two cameras and the possibility to install a power supply nearby, or power supply by free pairs of Ethernet cable a few meters away, you can save money on the injector or a special switch, but for the professional installation of CCTV like “kolhoza” should be avoided.

SKAT PoE switches

Russian company Bastion to increase the connection range of IP-cameras offers to install special switches with built-in power supply, providing power of 30 watts per channel. The manufacturer claims a range of up to 250 meters through the PoE switch SKAT support VLAN.

An approximate wiring diagram looks like this.

Conventional IP video cameras without PoE support can be connected via a splitter. And using a repeater will add another 100 meters to the connection range.

  • Available with 4 or 8 ports. Suitable for small installations or individual segments of larger surveillance systems.
  • 4 kV lightning protection.
  • Stabilized power supply with 30W/channel. Sufficient for outdoor cameras with powerful IR illumination.
  • Reliability. MTBF is 50 thousand hours. 5 years manufacturer warranty.

Buy PoE switches SKAT with delivery to Technical Laboratory.

How to connect a CCTV camera via twisted pair

Let’s break down a few ways to connect power and data to digital surveillance cameras:

If the distance of the wire from the power supply to the camera allows us to connect directly, for example for a room camera, we simply plug in the connectors

In case of remote location of the camera from the server, you can use part of the vitocoupler cable for power and part for data in order not to lead 2 wires (network and power).

4 Wires should be crimped in a certain way in the connector, and the other wires can be used for power supply.

If this option is chosen, clamp the network cable cores stripped of the plastic braid from one side to the terminal block of the power supply connector

Crimp the twisted-pair wires at the other end in the same way. However such way has a disadvantage, namely when stripping strands it is easy to cut a copper wire in a place of shearing the plastic braid, which will make it fragile when bent, so the blade of the knife when pressing cannot be put perpendicular to the wire, you must cut at an angle, to avoid cutting the strand, which requires certain skills.

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PoE splitter can be used to improve the reliability of this type of connection. No bare wires provides additional protection against possible ingress of precipitation in the junction box on the street, as well as from the breakage of the wire when bent.

The kit comes with a pair of splitters. at both ends of the network cable connection

At the same time, as mentioned earlier a large number of network cameras are powered via PoE. At least all the cameras Hikvision have this function by default.

For ip-camera differentiate between PoE power supplies:. PoE switches (switch). PoE video recorders (NVR). PoE injectors (pictured right, this is the device, which can supply power and data to the camera on a network cable twisted pair. Has two RJ 45 outputs)

The first is data (Data) connect to the network, in our case directly to the router The second port goes power and data (DataPower) to the camera through a single network cable. Thus, using PoE technology, the number of connections is minimized, which increases the reliability of the system.

Connecting an analog video camera over twisted pair

Analog video surveillance over twisted pair is created by connecting the transceivers in the line.

Connecting an analog video camera without transmitters, even at a distance of 5 meters, degrades the quality to unrecognizable.

A huge advantage of twisted pair over coaxial cable, is the number of connected cameras. On one 4-pair Lan cable can be fully connected 2 video cameras, t.e to supply signal and voltage at the same time.

Connecting an analog video camera over twisted pair is very simple. To do this, you need to select the color of the necessary pairs to connect the transceiver and power plug on the video camera side and duplicate the sequence at the end of the line on the video recorder side and the power supply.

Twisted pair power supply is correct for the distance not exceeding 30 meters. When you increase the distance beyond 30 meters the voltage begins to drop because of the small cross section of cable.

Connecting an IP camera over twisted pair

To connect digital IP cameras use the same UTP cable with crimped RJ-45 connectors at both ends. Its advantage is the possibility of laying a single common twisted pair line for the entire system of IP surveillance cameras, using a switch (switch).

According to the standard TIA/EIA 568-5-A for cable category 5e, the maximum length of the cable segment is 100 meters, and the use of injectors and splitters PoE does not allow to increase this distance. How to overcome this 100-meter limitation? The old answer with fiber optic.