Using one Cat-6 Cable for two Cameras!

[cgcmgr 0]

First off, I'd like to say hi to everyone. Secondly, If I'm posting in the wrong forum, please excuse me, there are so many different forums to post in and I think this one is correct. If not, please feel free to move it.

 

Ok, so let's get to my situation. I'm looking to run 2 cameras with the use of just one Cat-6 cable. This means I would be using the single Cat-6 cable to transmit data and power as well.

 

I currently have an analog camera with good IR Light connected to a Cat-6 cable via video baluns. Data and power run through the Cat-6 cable. The cable runs is approximately 200'. I want to add an IP PTZ camera to the same place as the analog camera and connect it using the same one Cat-6 cable. The IP cam doesn’t have IR and I was hoping to use the analog’s IR so that the IP camera could “see” in the dark. I would be disabling any data to the analog camera, all I need is power for it (to power the IR Leds).

 

Here is why I believe I can do it:

Looking at different Modes of PoE, there is Mode A and Mode B. Mode A sends power over the same 2 pairs of wires that data is sent over. This would be pins 1,2,3,& 6. So I could run a PoE IP PTZ camera using a PoE Injector that utilizes Mode A. Now, this leaves me 2 unused pairs on pins 4,5,7 & 8. I figured if I cut off the RJ45 plug on both ends of the Cat-6 cable, I could put a new RJ45 plug onto the cable connecting the pairs of wire to only pins 1,2,3 & 6 and then another RJ45 plug to the cable connecting the pairs of wire to only pins 4,5,7 & 8. Both ends of the Cat-6 cable will have 2 RJ45 plugs. I'd connect the RJ45 plug using pins 1,2,3 & 6 to a Mode A PoE Injector and it's match on the other end to the IP camera and then connect the 2nd RJ45 plug using pins 4,5,6 & 8 to my existing video Balun and then on the camera side connect the RJ45 plug to the receiving Video Balun and then to the analog IR camera.

 

This seems like it would work, but I would need to know what pins baluns send data over and what pins they send power over so that I could connect the pairs of wires to the correct pins. I will NOT be in any need of data for the analog camera.

 

This brings up a few questions:

1. Is this feasible? Will this idea work?

2. If it will work, are there any better suggestions to use just one Cat-6 cable?

3. What pins do video baluns send power and data over?

4. Does anyone know of any PoE Injectors that use Mode A? Cable run is 200' so I need something capable of that length.

 

Sorry for all the questions, but I'm very new to this technology and I'm trying to learn

 

Thanks,

Chris

[Soundy 1]

1. Is this feasible? Will this idea work?

No. You've put a lot of thought into it, but the one thing you're missing is the current requirements for the IR, which alone will probably be over 500mA. When this plan is said and done, you'll have only one pair running power to the analog camera, to carry anywhere from 500mA to 1A - at 200' that simply isn't sufficient.

 

2. If it will work, are there any better suggestions to use just one Cat-6 cable?

There's no way to do this that doesn't require either a second power wire, or powering at least the analog camera locally. The ideal method would be to add an IP encoder for the analog camera, run that and the PTZ into a switch, and just feed them both over the network.

 

Actually, I shouldn't say NO way, since it would theoretically be possible to tap off the PoE power and feed it through a voltage regulator to knock it down to 12V for the IR camera... but with the IR, and the current demands of the PTZ, you're probably going to exceed the 15.4W spec for the PoE supply.

 

3. What pins do video baluns send power and data over?

There is no "standard" for this; it depends on the baluns.

 

One other problem with your plan: it's highly unlikely that your PTZ will work with the other camera's IR. Except for cheap color IR cameras, all color cameras include an IR-cut filter over the sensor, since IR wavelengths tend to have negative effects on the color balance.

[cgcmgr 0]

Thanks for the quick reply.

 

As far as the IR goes, the IP PTZ cam has a removable IR-Cut filter. Once it becomes dark enough the filter moves away from the lens, so that should work.

 

Secondly, you said "No. You've put a lot of thought into it, but the one thing you're missing is the current requirements for the IR, which alone will probably be over 500mA. When this plan is said and done, you'll have only one pair running power to the analog camera, to carry anywhere from 500mA to 1A - at 200' that simply isn't sufficient."

 

I thought I would have 2 pairs carrying the power, those going to pins 4,5,7 & 8. The IR lights up now using the baluns so the 200' doesn't seem to be a problem. What if I don't use baluns and use a Mode B PoE injector. That puts power over pins 4,5,7 & 8. A splitter on the other end would receive the power on those 4 pins and then it would plug into my IR camera. I don't need to connect the Lan part as I wont be using data.

 

I'm just throwing out ideas here. You guys know better than me.

 

Chris

[Soundy 1]

Analog-over-baluns and IP cameras are two different beasts.

 

10/100 ethernet normally uses two pairs. Mode A PoE runs power over those same pairs; Mode B puts power on the two unused pairs. PoE power is nominally 44VDC at up to 15.4W. So at the very least, your IP camera will require two pairs *to itself*. PTZ control would be via network so separate data pairs are irrelevant.

 

That leaves two pairs for the analog camera.

 

Analog baluns use one pair for video, period; yours are probably using the other three for power. If you steal two pairs for network, that leaves only one for power. Quick math, assuming the IR camera requires a nominal 750mA, at 200' you're looking at a loss of 3.5V, meaning the camera will only see 9.5V. With three pairs, there's only 0.8V loss.

 

All the PoE splitters I've seen use mode B; all they do is take that power off and regulate it down to 5 or 12V. With mode B power, you don't have an available pair for analog video. Otherwise, you COULD theoretically take that 12V and power both cameras, but again, you have to look at the maximum power requirements for both. Assuming the IR camera is 750mA, that's 9W right there, leaving only 6W to power your PTZ. IP cameras tend to have higher power requirements than analog cameras to begin with, and PTZs tend to be power-hungry as well, and I suspect there won't be enough to run both cameras.

 

Of course, I can only guess at the numbers, because you haven't provided any details on either camera, but I would be really surprised if the two together take anything under 17-18W.

[nDAlk90 0]

Soundy you and your Canadian friends sure are knowledgeable.

If only some of your American counterparts shared their knowledge as willingly as you do...

 

Analog-over-baluns and IP cameras are two different beasts.

 

10/100 ethernet normally uses two pairs. Mode A PoE runs power over those same pairs; Mode B puts power on the two unused pairs. PoE power is nominally 44VDC at up to 15.4W. So at the very least, your IP camera will require two pairs *to itself*. PTZ control would be via network so separate data pairs are irrelevant.

 

That leaves two pairs for the analog camera.

 

Analog baluns use one pair for video, period; yours are probably using the other three for power. If you steal two pairs for network, that leaves only one for power. Quick math, assuming the IR camera requires a nominal 750mA, at 200' you're looking at a loss of 3.5V, meaning the camera will only see 9.5V. With three pairs, there's only 0.8V loss.

 

All the PoE splitters I've seen use mode B; all they do is take that power off and regulate it down to 5 or 12V. With mode B power, you don't have an available pair for analog video. Otherwise, you COULD theoretically take that 12V and power both cameras, but again, you have to look at the maximum power requirements for both. Assuming the IR camera is 750mA, that's 9W right there, leaving only 6W to power your PTZ. IP cameras tend to have higher power requirements than analog cameras to begin with, and PTZs tend to be power-hungry as well, and I suspect there won't be enough to run both cameras.

 

Of course, I can only guess at the numbers, because you haven't provided any details on either camera, but I would be really surprised if the two together take anything under 17-18W.

[cgcmgr 0]

Analog-over-baluns and IP cameras are two different beasts.

 

10/100 ethernet normally uses two pairs. Mode A PoE runs power over those same pairs; Mode B puts power on the two unused pairs. PoE power is nominally 44VDC at up to 15.4W. So at the very least, your IP camera will require two pairs *to itself*. PTZ control would be via network so separate data pairs are irrelevant.

 

That leaves two pairs for the analog camera.

 

Analog baluns use one pair for video, period; yours are probably using the other three for power. If you steal two pairs for network, that leaves only one for power. Quick math, assuming the IR camera requires a nominal 750mA, at 200' you're looking at a loss of 3.5V, meaning the camera will only see 9.5V. With three pairs, there's only 0.8V loss.

 

All the PoE splitters I've seen use mode B; all they do is take that power off and regulate it down to 5 or 12V. With mode B power, you don't have an available pair for analog video. Otherwise, you COULD theoretically take that 12V and power both cameras, but again, you have to look at the maximum power requirements for both. Assuming the IR camera is 750mA, that's 9W right there, leaving only 6W to power your PTZ. IP cameras tend to have higher power requirements than analog cameras to begin with, and PTZs tend to be power-hungry as well, and I suspect there won't be enough to run both cameras.

 

Of course, I can only guess at the numbers, because you haven't provided any details on either camera, but I would be really surprised if the two together take anything under 17-18W.

 

Soundy, you're very helpful. I'll look at the specs of the cameras and report back as soon as I can. What about using a high powered PoE Injector like the Axis T8121 High Power PoE Midspan 1-Port 5014-004. It has this spec. 55 V DC (max. 30 W) It has 30W not the normal 15.4W. Using a 12V splitter would regulate the voltage to 12V. Would this work or is the fact that is it regulated down to 12V means there still wont be enough wattage?

 

I see you're from Vancouver, I'm from New York. Looks like we may have a rematch of the '94 Stanley Cup this year. Both the Rangers and Canucks look good.

[hardwired 0]

I did find a high power 802.3at mode A injector here http://www.midspans.com/pdf/POE36U-1AT.pdf with a PoE passthrough splitter + 12VDC output here http://www.phihong.com/html/poe21-120h_21w_dc-dc_splitter.html.

 

You still will only have 10 Watts for PoE, and 12 Watts for the 12VDC output though, probably still not enough for the application described.

 

******Edit******

I'm American, BTW.

[nDAlk90 0]

******Edit******

I'm American, BTW.

 

That's good to hear... Let me guess you are not from the North East of the US...

 

Edit:

I hope I didn't offend anyone from North East U.S...

 

Let me tell you why I said this... I'm always on the lookout for new products and as such call and interact with many people regularly. I have noticed that people from densely populated areas tend to be a little more resistant to sharing their knowledge with others and are less friendly in communication style...

 

One example: I call a company in NYC who is a OEM of CCTV Equipment... You would be amazed at how inpatient the salesman was in explaining to me the difference between two products... I call a canadian company and ask when a version of a software comes out. Even though they claimed not to know you wouldn't believe how thorough and polite they were in explaining this fact and how they made an extra effort to impress the customer...

Edited April 4, 2012 by Guest

[cgcmgr 0]

I did find a high power 802.3at mode A injector here http://www.midspans.com/pdf/POE36U-1AT.pdf with a PoE passthrough splitter + 12VDC output here http://www.phihong.com/html/poe21-120h_21w_dc-dc_splitter.html.

 

You still will only have 10 Watts for PoE, and 12 Watts for the 12VDC output though, probably still not enough for the application described.

 

******Edit******

I'm American, BTW.

 

Thanks, I'll take a look

[cgcmgr 0]

Ok, so here are the specs of the cameras.

 

Soundy you were right:

 

The IP camera is 12VDC + or - 5% at 14.5W max

The existing analog camera is 12VDC at 360mA, but I was going to replace that with a camera I had laying around that is 12VDC at 700mA

 

Any way you can see this working with the 700mA camera and the IP camera and the use of High Powered PoE Midspans?

 

Chris

[Soundy 1]

I see you're from Vancouver, I'm from New York. Looks like we may have a rematch of the '94 Stanley Cup this year. Both the Rangers and Canucks look good.

Yes indeed! Bit of a barnburner going on right now with the Ducks in town - 4-3 Ducks in the 2nd. (Edit: make that 4-4 at the second intermission)

 

The IP camera is 12VDC + or - 5% at 14.5W max

The existing analog camera is 12VDC at 360mA, but I was going to replace that with a camera I had laying around that is 12VDC at 700mA

 

Any way you can see this working with the 700mA camera and the IP camera and the use of High Powered PoE Midspans?

700mA @ 12V is still 8.4W, for 22.9W total (keep in mind too, that the spec is measured at the supply end - it has to allow for losses over a longer run, included losses in the power splitter itself).

 

If you can use a 30W injector, you might be okay... BUT... you'll want to make sure that's still only using two pairs, because you'll still have to separate out one pair to be dedicated to the analog run. If the higher power is achieved by using all four pairs for power, you're hooped - the only option then would be a switch and an IP encoder, and those would have to run off the same power as well, which would definitely put you WAY over the limit.

[cgcmgr 0]

I see you're from Vancouver, I'm from New York. Looks like we may have a rematch of the '94 Stanley Cup this year. Both the Rangers and Canucks look good.

Yes indeed! Bit of a barnburner going on right now with the Ducks in town - 4-3 Ducks in the 2nd. (Edit: make that 4-4 at the second intermission)

 

The IP camera is 12VDC + or - 5% at 14.5W max

The existing analog camera is 12VDC at 360mA, but I was going to replace that with a camera I had laying around that is 12VDC at 700mA

 

Any way you can see this working with the 700mA camera and the IP camera and the use of High Powered PoE Midspans?

700mA @ 12V is still 8.4W, for 22.9W total (keep in mind too, that the spec is measured at the supply end - it has to allow for losses over a longer run, included losses in the power splitter itself).

 

If you can use a 30W injector, you might be okay... BUT... you'll want to make sure that's still only using two pairs, because you'll still have to separate out one pair to be dedicated to the analog run. If the higher power is achieved by using all four pairs for power, you're hooped - the only option then would be a switch and an IP encoder, and those would have to run off the same power as well, which would definitely put you WAY over the limit.

 

One last go at it. I found this High Powered PoE Injector (thanks to Hardwired) http://www.midspans.com/pdf/POE36U-1AT.pdf. It puts data AND power over pins 1,2,3 & 7. Then this splitter http://www.phihong.com/html/poe21_21w_dc-dc_poe_splitter.html would connect to my IP Camera. The IP camera also has a power dongle so I'd connect the dongle from the splitter to that. This splitter can receive power from either data or spare pairs. That's 21w to the camera that only needs 14.5w max. This allows room for more loss. All this is done over pins 1,2,3, & 7, leaving 4,5,6 & 8 free. I could use a regular PoE injector such as this http://www.ebay.com/itm/Pacific-Wireless-POE-12i-Power-Over-Ethernet-Injector-12V-PoE-/350554725063?pt=LH_DefaultDomain_0&hash=item519eb09ac7 which sends power over pins 4,5,6 & 8. What are we looking at 15.4W being produced? This would connect to a splitter that would connect to my IR camera (8.4W). Most splitters receive power over pins 4,5,6, & 8 which is exactly what I need. Again, only power is needed to the IR camera, not data so I can use those remaining two pairs. Even with a 200' run, with a loss of 3.5V, that's 9.5V * 1.3A = 12.35W. This even allows for more loss for cable length and splitter conversion. Looks like it would work, what do you think?

 

Chris

[Soundy 1]

You still need analog video from the analog camera, and that requires its own pair, period, end of story. You can't run power on that pair.

[jeromephone 6]

are you able to run another wire but just choose not too? I would think if it is possible running another cable

you would save a whole lot of potential issues. If the cable is around 15 cents a foot you are only looking at 30.00

[cgcmgr 0]

You still need analog video from the analog camera, and that requires its own pair, period, end of story. You can't run power on that pair.

 

This is what is confusing me. I don't need analog video. I do not want to use that camera for anything other than the IR. I will not have the video connected on either end. It's kind of like using a stand alone IR illuminator. All I want to do is power it up.

[cgcmgr 0]

are you able to run another wire but just choose not too? I would think if it is possible running another cable

you would save a whole lot of potential issues. If the cable is around 15 cents a foot you are only looking at 30.00

 

 

I agree that would be the easier way and probably less expensive way, however, to run this cable is a major headache. It isn't a straight run. I'm using my cameras in upstate NY where the area is pure country. The cable is run to a field through trees up and down hills. Then I have to bring it into the house near the top of my roof so that it isn't hanging low by the house. I'd have to get the extension ladder, then drill another hole into the house and feed it through etc. It's a lot of work and took me a few hours to do. Unfortunately, I'm not there that often, maybe every 3 months and only for like 2 days. I just don't have the time.

 

If all else fails, I guess I'll have to set aside a weekend and run another cable.

 

Thanks for your input

 

Chris

[Soundy 1]

Ooooooh, okay, I guess either you weren't clear about that before, or I just missed it.

[cgcmgr 0]

Ooooooh, okay, I guess either you weren't clear about that before, or I just missed it.

 

Don't worry about it, it's hard to follow what people are trying to convey when writing. So it looks like I can do it.

 

I thank you very much and wish your Canucks well in the Western Conference Playoffs. If they meet up with the Rangers in the Stanley Cup, well that's all the luck I can give you.

 

Thanks Again,

Chris

[Soundy 1]

Rangers won't get past the second round, so it's all good

 

Anyway, if you're splitting off two pairs to power the IR, it's probably more efficient to just power it directly with 12V rather than feed a separate high-power PoE injector and splitter over it. If the camera and IR run with three power pairs now, you SHOULD be fine running just the IR off two pairs. Worst case, use an adjustable power supply, measure the voltage at the camera end, and bump it up a bit so you get 12V at the camera.

[cgcmgr 0]

Rangers won't get past the second round, so it's all good

 

Anyway, if you're splitting off two pairs to power the IR, it's probably more efficient to just power it directly with 12V rather than feed a separate high-power PoE injector and splitter over it. If the camera and IR run with three power pairs now, you SHOULD be fine running just the IR off two pairs. Worst case, use an adjustable power supply, measure the voltage at the camera end, and bump it up a bit so you get 12V at the camera.

 

Thanks Soundy....been a great help.

[cgcmgr 0]

Hey Everyone,

 

Just wanted to report back on my progress. I finally set everything up this weekend and when I powered up my PoE Injectors.............nothing happened. The PoE splitters did not power up (lights did not light up). I had made a sort of Y-Cable out of a Cat-5e cable with 2 pairs of wire to one RJ45 connector and the other 2 pairs to a different RJ45 connector. I disconnected that cable and connected the main Cat-6 line to one PoE Splitter and it light up and gave power to the camera. I figured there was a problem with the Y-cable I had made (although I had tested it at home) and went to make a new one. Then it dawned on me that I was using a RJ45 coupler to connect the main cable to my Y-cable. I tested the coupler on a something else I had an it didn't work. I then took a known working coupler and tried it in its place and everything worked. It's nice when things work. It's funny how something as small as a coupler can cause such problems. This is the second time a coupler has done me in.

 

Anyway, just wanted to thank everyone for all the help

 

Chris