data over 'twisted' pair in elevator

[nhfire77]

I was asked by a friend to ponder on an issue. 20 story building with an elevator . IP security cameras were added to each of the elevator cars.

The elevator company provides the cable from the machine room to a j box on the top of the car directly over the camera.

The cable is looks like a thin walled SJ cable with 4 pairs of individually shielded twisted 18/2. It is not twisted like a CAT cable is of course. The elevator company states the cable is 225'. Continuity has been tested ad confirmed, camera works when powered on the car top.

The POE passes from the switch in the elevator machine room to the camera, but not data. (I know it's not a CAT 5/6, what did he expect to happen )

The elevator has RS-485 for an access control reader and that works flawlessly. (again I understand it's not the same)

The elevator company maintains this cable has been used for cameras before (it is not known if they meant IP or analog), and they maintain its the only twisted pair type cable for elevators . There was not written spec defining the required cable, so it's a lot of finger pointing right now.


-whom here has passed any form of IP data in to an elevator and how?

-any thoughts on if that cable could ever work?

 

[GoldDigger]

I was asked by a friend to ponder on an issue. 20 story building with an elevator . IP security cameras were added to each of the elevator cars.

The elevator company provides the cable from the machine room to a j box on the top of the car directly over the camera.

The cable is looks like a thin walled SJ cable with 4 pairs of individually shielded twisted 18/2. It is not twisted like a CAT cable is of course. The elevator company states the cable is 225'. Continuity has been tested ad confirmed, camera works when powered on the car top.

The POE passes from the switch in the elevator machine room to the camera, but not data. (I know it's not a CAT 5/6, what did he expect to happen )

The elevator has RS-485 for an access control reader and that works flawlessly. (again I understand it's not the same)

The elevator company maintains this cable has been used for cameras before (it is not known if they meant IP or analog), and they maintain its the only twisted pair type cable for elevators . There was not written spec defining the required cable, so it's a lot of finger pointing right now.


-whom here has passed any form of IP data in to an elevator and how?

-any thoughts on if that cable could ever work?

Under those circumstances, I would consider using a WiFi router (or more than one) placed inside the elevator shaft and a WiFi adapter on the elevator (maybe the two antenna kind with one antenna remotely located at top and one at bottom of the elevator car.)
I do not see any way that the cable could be made to work reliably for twisted pair IP equipment designed for CAT5 wiring.

On the other hand, there are IP transceivers which are designed to piggyback over power wiring or to use common twisted pair wire. A pair of those should also work for you.

 

[nhfire77]

I had considered the HD-SDI style camera. One of the shielded pairs could take place of a coax, the shield is a full copper braid.

It hasn't been determined who will eat this or if the client will pay due to the ambiguity. And it's not just one elevator.......

 

[nhfire77]

And as you said the IP transceiver systems as well, it adds another level of complication which is unfortunate.

Im lost as to the elevator company telling them CAT rates cables arent available to be put in the travel cable. Seems like this has to have come up before.

 

[gadfly56]

Under those circumstances, I would consider using a WiFi router (or more than one) placed inside the elevator shaft and a WiFi adapter on the elevator (maybe the two antenna kind with one antenna remotely located at top and one at bottom of the elevator car.)
I do not see any way that the cable could be made to work reliably for twisted pair IP equipment designed for CAT5 wiring.

On the other hand, there are IP transceivers which are designed to piggyback over power wiring or to use common twisted pair wire. A pair of those should also work for you.

Careful trying to place "foriegn" equipment in the elevator shaft. There are some pretty strict rules regarding what's allowed in the shaft or the elevator mechanical room, for that matter.

 

[Fulthrotl]

Careful trying to place "foreign" equipment in the elevator shaft. There are some pretty strict rules regarding what's allowed in the shaft or the elevator mechanical room, for that matter.

that was my first thought. you really need a UTP to get an ip device to work reliably.
or token ring, and that is limited to 16 mbps, and that won't carry any higher resolution
video than the 1969 moon walk.

the wifi might be a better solution, as long as you didn't put the devices directly in the shaft.
i can't see that getting by final inspection. as dumb as it sounds, i'd look at 802.11 ac routers
bridged every four floors. that would allow you to put a camera in every car, and the range on
ac wireless points is remarkable. i'm using apple airport extreme's, and i can stream video
200' away from the thing. the good thing about the airports is you can hit one with a cat 5 or 6,
and bridge them all together, up to five, and they all work excellently... about $190 each, retail
i think they are.

 

[nhfire77]

From the info I gathered there is a large nema 1 box on the car roof just for the camera connection, big enough for a transceiver etc. But it would have to get POE or POE derived power, I'm sure nothing can be connected to anything elevator.

I was told wifi wasn't going to be considered for this.

Yes things in the shaft will have to be avoided and the elevator mechanics must be present, actually install and approve of anything that occurs in the machine room or shaft, no one can even enter those rooms without them. Luckily it's not my job, just a crappy situation for a business associate.

 

[zbang]

that was my first thought. you really need a UTP to get an ip device to work reliably. or token ring, and that is limited to 16 mbps, and that won't carry any higher resolution video than the 1969 moon walk.

You might be able to get 10Mbps ethernet down that cable, which will give you perfectly fine resolution if you don't need 30 FPS. Used to be able to get ethernet line drivers that would fire a signal down generic phone wires, but AFAIK they've all disappeared from the market. Tut Systems comes to mind for that, but they're gone.

 

[erickench]

Everything is becoming digital including security camera systems. They usually operate on ethernet and would require a Cat 5, 5e, 6, or 6a cable. The only time that you could construct a hybrid system is when you have a coaxial cable that used to work on analog. You could very easily convert this to an ethernet system. But I do not think that you could use twisted pair analog for digital in this case.

 

[nhfire77]

It is TCP/IP/POE they are trying to push down the cable.

I just stumbled across a system that does this. It does full POE+ over a single pair of 18/2. I'm left wondering if there are more options.

http://www.nvt.com/assets/en-us/eo2_datasheet_en-us.pdf

 

[Rampage_Rick]

The cable is looks like a thin walled SJ cable with 4 pairs of individually shielded twisted 18/2. It is not twisted like a CAT cable is of course. The elevator company states the cable is 225'. Continuity has been tested ad confirmed, camera works when powered on the car top.

I've run card-swipe readers over that exact type of cable, but never ethernet. Point of issue: if you're ever involved in a new elevator installation, request one or more UTP cables within the traveller. It costs very little to add initially, but costs incredibly more to retrofit. Anyways, there are multiple solutions here.

1) Wireless - They do make wireless video transmitters specifically for elevator cars. Might be able to get away with commercial-grade WiFi assuming you used directional antennas on the cab and the top of the shaft.

2) Analog video - You should be able to run analog video over a single pair using video baluns, such as those from Muxlab or Nitek. This implies an analog camera in the elevator car, and possibly an analog>IP encoder if the CCTV system is digital.

3) Digital - There are multiple ways to run ethernet over a single pair. Some SDSL and VDSL modems can be configured to work back-to-back over any unpowered circuit (there are stories of connections run via barb wire fence) I've previously worked with Xpeed X320R modems that are still going strong 8 years later, however they're a bit slow at 2.3 MBPS. I see that StarTech makes a VDSL2 ethernet extender that's under $370. I would expect speeds above 50 MBPS with these units. Personally this would be my first choice to try.