Everything about powering devices in the network, i.e. POE - also from the pract

From the experience and definition of POE, we divide into passive and active.
PASSIVE POE IS NOT COMPATIBLE WITH ACTIVE POE
In short, passive POE is "POE for everyone" or "Adam Słodowy - POE"

PASSIVE POE:
- all kinds of connections where SAMI deliberately let the power into a free twisted pair. With the help of POE adapters or simple injectors or perfidly soldering into the twisted pair - here we can let in power from 12VDC 24VAC up to even 48VDC! There is no rule here as to how long this power supply will go - we have to calculate everything ourselves.
Whether we let go of the power supply with two or four wires - it's up to us to choose.
The advantages include:
- price of accessories
- freedom of power supply (there will always be a power supply or transformer)
- the possibility of making a connection ... even with a transformer soldering iron
- possibility of powering other devices, e.g. 12VDC
Defects:
- we do not know how far the power supply will reach us
- we have to watch out for voltage drops
- low prevalence

However, it is quite different in POE Active
POE Active - it is a POE which, through standardization, defining the minimum conditions for cabling, gives us a certain guarantee of transmitting a certain power over a certain distance. We are not interested in what kind of veins the power transmission is realized.
Here we have 802.3af (15.4W, 100m 12.95W), 802.3at (34.2W, 100m 29.50W).

In active POE, you have to remember that it cannot be done "cottage-house" by letting 48V into 4 wires (passive) - and finally the 802.3af (active) camera will start working. Here we have a special procedure for initiating a connection and POE power supply - which two devices need to "know".
The advantages include:
- certainty that at 100 meters we have the power we want (although I recently powered the IP tube camera after 120 meters)
- speed ... we tighten and it's ready
- most devices operate in this standard
- the connections are backwards compatible - i.e. we can connect devices operating in the 802.3afz 802.3at standard.
Defects:
- it's hard to connect other devices, e.g. 12VDC
.... hard to find


As for POE + - this was absorbed by 802.3at. On the other hand, HI-POE - it is used to send 60W twisted pair - is used in more specific topics.
Of course, these two solutions are included in the active POE type - that is, they are "backwards" compatible, ie each such power supply can work with 802.3af and 802.3at devices.

To sum up:
The market is dominated by 802.3 af and 802.3at (POE active) - in the case of cctv, 12 or 29 W power is enough. Sometimes it happens that the PTZIP rotary camera needs 802.3at - then it is enough to buy a special power supply for 70 PLN - and the problem is over.

On the other hand, passive POE - self-made reigns here So who can do it. It's better not to do it when we don't know each other. Better not to mix passive POE with ACTIVE POE.

jpl wrote:

PASSIVE POE IS NOT COMPATIBLE WITH ACTIVE POE

Why do you think so? After all, by powering cameras in the 802.3af standard with an ordinary power supply by letting 48V on idle pairs, everything will work properly. One downside to active POE is the possibility of damaging the equipment if the wires are not connected properly. Active PoE is intelligent and does not give 48V before connecting and testing the device as it happens in passive.
Powering a standard camera with a power consumption of 10W with 48V, using 2 pairs, the voltage drop on the most popular cat 5e, AWG24 will be only 1V. And the cameras should accept a voltage below 40V.

azande wrote:

After all, by powering cameras in the 802.3af standard with an ordinary power supply by letting 48V on idle pairs, everything will work properly.

Have you ever tried to do that? Solder with the 48V power supply ... And so power the camera working on 802.3af ... at a distance of 50 meters. We'll see if the POE fires.

I tried, at 100 meters it worked, at 300 meters the camera was also properly powered. I don't understand why it wouldn't work.

azande wrote:

I tried, at 100 meters it worked, at 300 meters the camera was also properly powered. I don't understand why it wouldn't work.

I suggest reading, although a little out of date probably:
http://elektronikab2b.pl/technika/10311-poe-czyli-power-over-ethernet-po-tuningu#.Uxc6jYWeYmk

And in terms of clarification, the 802.3af standard defines two types of power supply:
A pins 1,2,3,6 (power in pairs with data)
B pins 4,5,7,8
Both of them are perfectly correct and acceptable to use, the most common being A, most PoE switches start with power from it.

However, it is worth paying attention to the fact that some devices cannot work on any type, but have predetermined which pairs are poe pairs, this usually applies to Chinese budget products, both switches and receivers.

Yca wrote:

And in terms of clarification, the 802.3af standard defines two types of power supply:
A pins 1,2,3,6 (power in pairs with data)
B pins 4,5,7,8
Both of them are perfectly correct and acceptable to use, the most common being A, most PoE switches start with power from it.

However, it is worth paying attention to the fact that some devices cannot work on any type, but have predetermined which pairs are poe pairs, this usually applies to Chinese budget products, both switches and receivers.

Ok, you should also pay attention to the type of PoE in the camera.
I tested on a brand and budget camera, both took power on idle pairs (type B).

I will only add that:

PD - power device (e.g. camera)
PSE - power source equipment (power supply, e.g. switch with poe)

This is how it is defined in PoE and from what I read somewhere, PD devices (camera) are not required to work in any of the variants (pins with voltage), but the PSE (power supply) is required to adapt to the PD device (i.e. switch with poe) 802.3 .. must be able to distribute on both sets of pairs).

From what I noticed, the PSE dictates which pairs get the power, some are tested, if it does not sense PD, it goes to testing the other.

Quote:

PSE (power supply) has to adapt to the PD device (i.e. switch with poe 802.3 .. must be able to distribute on both sets of pairs).

I honestly did not hear this, I admit it makes sense. On the other hand, I have seen PSD devices described as compliant with the standard, but they could not be powered in both modes.

As they say, not all that glitters is gold ...

But I made the bull, okay, just swapped PD roles with PSE. Below is a quote from one PDF document (rather credible I think).

Quote:

The Power Device has to support both versions, Phantom- and Spare pair power. With the Power Sourcing Equipment it is different, the manufacturer has the choice which version he wants to support.

Link to the article:
http://belden.com/docs/upload/PoE_Basics_WP.pdf

So it turns out that the PD (e.g. camera) must support both methods of voltage reception, i.e. what my colleague Yca wrote is correct.

In general, the entire test consists of, among other things on the fact that:

1.) Device detection:
PSE gives a voltage of 2.5-10 V to the power cable to the PD for about 500ms. Intensity max. 30mA (safe). If the PSE (power supply) detects a current flow, i.e. that something is connected at the other end of the RJ-45.

2.) Classification:
The PD (eg camera) "attaches" a resistance of around R = 25 kohm to the appropriate pins. Accurate measurement of this R (resistance of the entire line, and more precisely the current flowing in this line I = U / R) through PSE shows how much power the PD works with (e.g. max. 15.4W) - if it works at all.

3.) Commissioning:
Gradual voltage increase provided by PSE, stabilization of the converter, etc.

So this tells us that the power supply is not stupid and if it sees no reasons to give this voltage, it will not give it (e.g. a PoE switch is connected to a simple camera without PoE - if the power supply was pushing some current, it would could damage something on the camera). It is also important in my opinion, because we know that all this "negotiation" has nothing to do with negotiating over TCP / IP .. it's just a detection that the current is flowing and what value this current is.

In more modern versions of PoE, there is already some kind of communication on network protocols.

Adds a Linear document found somewhere on the specifics of initiating poe connections and the mode of operation, I recommend it for those who like to have elementary knowledge.

Hello.

I have installed several BCS cameras on the site and generally all of them work very well, except for one. The exact camera model is:
- BCS-TIP5200IR,
- power supply via POE
- cable length approximately 140m cat5e
- power consumed by the camera below 10W
- the voltage drop on such a section is about 4.5V
- switch NETGEAR ProSafe 10/100 Ethernet switch 16-port with 8-port PoE

After connecting the camera to the switch at the appropriate port, the right LED lights up green, while the left one (which indicates transmission) does not react and after a few seconds it turns orange. I got to the instruction of this switch and it would turn out to be a PoE error.

Do you think it's too far away?
Are there any PoE-powered switches that I could insert in the middle of the cable route to amplify the signal in case of too much distance (without placing new, additional cables)?

The standard says about 100 meters above you do it on your own responsibility, you can use the UBNT-POE-48-24W-G adapter

The easiest way is to switch to passive poe and use a converter that increases the voltage at the camera, e.g. ASUC25 / 48

I chose a different solution than what you proposed. I decided to lay additional cables and insert a PoE switch roughly in the middle of the cable length. This solution will give me the possibility of further expansion of the system.
However, if I did not install an additional switch, I would put a PoE Repeter that meets my requirements from the previous post in 100%.

Thank you for your help and best regards

Much, much depends on the quality of the cable, its arrangement and the camera itself. Personally, I tested PoE solutions where the Cat5e length was 100m and everything worked fine.

... study on the subject
http://belden.com/docs/upload/PoE_Basics_WP.pdf

I will join the topic - do POE cameras have any protection against wrong voltage? I noticed that the webcams working in the POE standard and those powered by 12V have the same pins on the built-in cable (RJ45 socket + power socket). What would happen if I connected such a 12V webcam to an active POE switch through a splitter (where, as we know, 48V flies) - would the camera survive it (some maintenance-free security system), would be repairable or rather definitely equipment for the trash?

You will find the answer in the study that I "linked" above
Page 3 exactly.

Added after 3 [minutes]:

Yca wrote:

Quote:
PSE (power supply) has to adapt to the PD device (i.e. switch with poe 802.3 .. must be able to distribute on both sets of pairs).

I honestly did not hear this, I admit it makes sense. On the other hand, I have seen PSD devices described as compliant with the standard, but they could not be powered in both modes.

As they say, not all that glitters is gold ...

Well, in theory everything looks nice, but is it the same in practice? I personally checked it only in the case of the novus 3000 series cameras. Here I know that the camera accepts power from both transmission wires (orange and green pair) and additional pairs, i.e. blue and brown. How do I know, I only connected it in two pairs to a switch that has the ability to supply power in both ways and to a switch sold by the pulsar company where "manufacturer" - I think you should use quotation marks in this case, clearly declares (plus for it) in the catalog card that this switch only powers the brown and blue pairs (but of course the af standard meets )
Let's take the DSG 108 switch as an example. Https://www.pulsar.pl/PL_79_DSG108_din,switch-10-portowy-dsg108-bez-silacza-do-8-kamer-ip

We can read in his card, among other things:

PoE supply - pairs: 4/5 (+), 7/8 (-)



I wonder what it is like with other devices?

I invite you to read the other guides, highlighted topics, articles in the field of security systems:
Stationary security. Alarm systems, Cameras, Intercoms, Gate and roller shutter drives, Home automation. Highlighted topics and guides.
If you do not find the answer to your question in the above-mentioned topics, please visit the forum:
https://www.elektroda.pl/rtvforum/forum77.html

I also encourage you to visit the General Guides section, where you will find materials from other forum sections, including those for people starting their adventure with electronics:
https://www.elektroda.pl/rtvforum/forum510.html

Dahua uses 4 veins. I used to cut the factory RJ connectors and punch a 4-pin M12.
Confirmation of my words in the post of my friend simsone:
https://www.elektroda.pl/rtvforum/topic3356277.html

As the subject interested me quite a lot, I built a "laboratory" so quickly for testing, I used:
YTKS 6x0,5 Madex cable (only 2 pairs of pins 1,2,3,6 are used), 70m section
Hikvision DS 2CD 1641FWD-I camera
Cisco Catalyst 3650 POE Switch
Switch Netgear Prosafe 24 POE

And I have to confirm the words of my colleague @Alpha is quite stable on this cable.

Geovision from Cisco SG300 also works on signal pairs. This trick does not work with a POE Airlive power supply

Thank you for the entries so far, including the last ones that show us how it all looks from the practical side.
Such knowledge is definitely useful when we want / have to connect something on cables that differ from the standard, in the case of removing and dealing with faults, or when we want / have to for some reason connect, for example, two cameras on one UTP cable.

The above entries show that most receivers are able to work on both types of power supply, but the cheaper POE switches rather supply power only on idle pairs. Or maybe someone has examples that contradict this thesis, or others that confirm it?

And what pairs, then, are the power supplied by POE switches built into the recorders. Anyone know something about this?

When talking about POE, it is impossible to mention specific "variants" of this standard (eg described as POE-net), which have nothing to do with this standard.
https://www.elektroda.pl/rtvforum/topic3550152.html#17758306

I found the Hika DS-7608NI-E2 / 8P / A recorder, I checked how it is with this POE in the built-in switches, so the built-in recorder negotiates POE, but on free pairs, i.e. 4.5, 7, 8 my YTKS 70m patchcord is not working for transmission, all wires are needed, tested with the camera and with the POE splitter and measured with a meter from the test monitor, also if we have to combine it, not with a recorder of this type ...