Jump to content

Looking for combined / hybrid cable


Recommended Posts

I've got a little project on the boil, trying to get some PTZ CCTV cameras working in an elegant and easily-deployable fashion. Partly for a demo rig but also on-stage use when things start back up again.


Ideally I'd send a 12v supply along with two twisted pairs: one to carry the video signal and the other for the RS485 that's used for PTZ control. The power required means that at 12v the current required is going to be too much for the standard twisted pairs, so I'm looking for an option that's got separate cores for power, ideally 1 mm2 cross-section but I could scrape by on less if I keep the lengths under control.


It's a bit of a challenge finding a suitable cable. I can turn some options up online, but like this they're aimed at wholesalers. I'm only needing a couple of hundred metres, not 200 boxes.


Struggling to turn up anything via Google, probably because any search terms are turning up irrelevant results about PoE or various baluns etc.


Has anyone come across a potential (UK based) supplier?

Edited by Stuart91
Link to comment
Share on other sites

  • Replies 33
  • Created
  • Last Reply

Top Posters In This Topic

Thanks, Dave. I might be missing something but it looks like the cable you've linked only has the standard four twisted pairs. More than ample for the signal transmission I need, but probably not enough cross-section for the 12v supply.


I've edited my original post since I suspect I wasn't clear enough.

Link to comment
Share on other sites

It is essentially CCTV cameras that I'm trying to run with this, so I've tried various suppliers and not found anything suitable. There's plenty of the traditional "shotgun" style cable around that has two-core power and an RG59 coax side by side. I'd take something like that if it had a CAT5/6 there instead of the coax.(There are versions that have CAT6 + coax with no power, but I can't see anything that's CAT5/6 + power)


Most IP cameras seem to be either mains powered or PoE - it seems like I'm sitting in a slightly awkward halfway house.

Link to comment
Share on other sites

Can't work out whether the camera you're referring to uses one twisted pair or one cable of several twisted pairs for the video signal. Assuming it's one pair I found the following with some extended googling


Twin DMX plus 2x1mm power: (Light grey, 200m drum ~€400) https://gothamcable.com/en/gothamcables/dmxled110ohm/10682frnc2dmx230vacfrncled

Sommer Monolith 2: Twin DMX plus 3x1.5mm power https://shop.sommercable.com/en/Cable/Bulk-Cable-Audio/DMX-Power-SC-Monolith-2-500-0051-2.html

Cordial CDP 2-25:: Twin DMX plus 3x2.5mm power https://www.cordial-cables.com/en/products/cdp-2-25

Syntax 7XD2F315SX: Twin DMX plus 3x1.5mm power http://syntaxcables.valentiniinternational.it/sito/schedaprodotto.php?id=13

Cat 6a plus 3x2.5mm power: https://kelseyacoustics.co.uk/product/kelsey-combi-2/

Twin DMX plus 3x1.5mm power: (seller in China) http://propaudio.com/product/hc02p15-composite-cable-power-3g1-5-2x-DMX-cable/

Cat 6 plus 2x LV power https://tmb.com/proplex-powerdata-lv/

Link to comment
Share on other sites

I’m assuming your cameras are IP cameras, since you mention using twisted pair for video transmission. What’s the maximum voltage you can send down Cat5/6? Since your problem seems to be that you need 12VDC at a reasonable current, can’t you bump up the voltage that you send over the Cat5 and then step it down again at the camera? Voltage goes up, amps go down.
Link to comment
Share on other sites

Guessing it's not IP, on stage use , lag may be an issue.


802.3BT is '100W' PoE, actually 72W delivered, at up to 56V.Switches are expensive.


PoE + delivers 60W at lower cost.


Mebbe use midspan injection and splitter to carry power and SD video.

Edited by musht
Link to comment
Share on other sites

TMB sell "shotgun" style dual Cat5e cable: here - you could use two of the pairs for video & RS-485, and the rest for power. By my reckoning, you have 12x 0.22mm2 conductors available for power.

In a similar spirit of combining lots of conductors, there's Canford 8-pair FSM which is a single 11mm diameter cable


I had wondered about running a higher voltage down the cable and then dropping it at the camera, but introduces more active devices in the system which could fail, cf. the passive approach of the "right" cable.

Link to comment
Share on other sites

Hi folks,

Thanks for all the contributions.


The camera's aren't IP, they are using TVI, which can run down bog standard RG59 coax but can also be adapted to come down one pair of a CAT5 or 6 cable. The control for the PTZ is RS485.


I'm keen to avoid a taped loom, partly for neatness but also for ease of deployment, I'm thinking I might be able to use a single connector (with a breakout box at the camera) if I can find a cable with a small enough outer jacket.


I'd originally hoped to be able to use a single CAT5/6 cable, using two pairs for the signal + control, and ganging the other two pairs together for power. But according to the manual the cameras will draw 1.7amps @ 12v. Plus I'm not sure how tight the voltage requirement is, I wouldn't want them flaking out if the delivered voltage drops over a longer run.


One suggestion I've had was to use 48v for the run, and step down at the camera. That would probably run happily down two pairs, maximum run is going to be 50m tops. But as Tom suggests it adds complexity, and I think I'd be happier getting the right cable, even if it means a bit of compromise on the form factor.

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue.