Cat 3 vs Cat 5 Cable ???????

[shoreviewsecurity 0]

Hey Everyone,

 

Need some advice here... I have a potential customer who has cat 3 already buried from one location to another and wants me to haul video over it. Now I have never hauled video over cat 3 but often over cat 5. I know cat 3 is not twisted and assume this will be an issue. Am I correct??

 

BTW about 300' and here's the kicker... wants to run 4 cams over this 24 pair along side telephony.

 

Thanks

 

Mike

[kensplace 0]

According to wikepedia cat3 is a twisted pair cable, so it may be worth checking to see if the cable is twisted or not...

 

http://en.wikipedia.org/wiki/Category_3_cable

 

Although I have not used cat3 cable for cctv, NVT's learning center states that their baluns can be used with cat2 or better cable, it also states that some people have had success with non twisted cable (but they dont recommend it)

 

Can Category 6 cable be used?

Yes. Unshielded Twisted Pair cable, Category 2, telephone or better, can be used with NVT.

Can un-twisted cable be used?

Some customers have successfully used untwisted cable. NVT does not recommend it due to its interference susceptibility.

 

link - http://www.nvtuk.com/learning.asp

 

They also state that there is no problem with multiple video signals in multi pair cables

 

Can I transmit more than one video signal in a multi-pair cable?

Yes. One of the benefits of using NVT transceivers is interference rejection. NVT video signals can reside in the same cable bundle as multiple video signals, Ethernet, 24VAC, RS-422, RS-485, etc.

 

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[shoreviewsecurity 0]

Thanks for the prompt reply. It is NOT twisted thus my concern and was installed primarily for his phone system between buildings.

 

Hmmmmm, let me give this some thought. I would hate to bid on this job expecting to use the cat 3 only to have a problem. May have to disclaim it to be on the safe side.

[wisp_engineer 0]

CAT3 for sure IS twisted. The twist rate however is much lower than that of CAT5 or higher Category ratings.

 

Old phone wiring is NOT twisted, meaning station wire such refered to as JK wire. It basically is like 2-wire home theater wire, where you have two PIC wires inside another jacket. I wouldn't suggest using JK for anything anymore these days as you are not afforded the noise cancellation features of CAT3 or higher cables.

 

25-pair phone cables are at a minimum CAT3. You can purchase 25-pair CAT5E cables as well but I doubt that is what you are dealing with. Most likely you are looking at 25-pair CAT3.

[shoreviewsecurity 0]

OK, maybe that's what is confusing me. From the little bit I saw it appeared untwisted. The other problem is I am going on memory as it has been about a year since I scoped this job. ( that's what happens when you get old ). The reason I am sure it is "cat 3" is because the customer said it was cat 5 and when I cross referenced the part number on the cable, it came back as cat 3. That I remember!! Customer has asked for a re-bid and my notes were not with the original bid in my file.

 

I may have to visit the property again and take a closer look at the cable. I can say this much though, it is new construction ( 5 years ) so I would assume it to be cat 3 and not JK.

 

Thanks again everyone for the feedback and your time

 

Mike

[wisp_engineer 0]

Where are you looking to see it is really untwisted? If it terminates at a 66-block you can bet it is going to be fanned out and untwisted quite a bit.

 

If you were to take a couple of feet of 25-pair CAT3 and remove the jacket, you'd see it was twisted just as much as your regular 3-pair CAT3 drop wire.

 

I know ADT has no issues running VID and PTZ control over CAT3 as I went up to bid against them on a job. They were going to use baluns to connect the PTZ to the DVR. Both were separated by some distance.... The only common point was the 25-pair cable running from one end of the factory to the other.

 

 

My only concern is you might get some noise issues from the POTS pairs in the cable. Are these digital phones or analog (POTS) phones?

[shoreviewsecurity 0]

Good point and yes, it was punched down and fanned out. OK, I feel better now knowing it has been done. Please don't misunderstand me... I just want to be sure before I bid on this as I have NEVER hauled video over cat 3. Better safe than sorry.

 

I believe it to be a digital system so I should be OK.

 

Thanks again!!

[wisp_engineer 0]

It's ok.

 

Neither have I...

 

 

 

I understand the concepts of transmission systems though. We run all kinds of things over 25-pair like audio, control, data, etc. Video really is no different other than it is just a higher frequency and a different form of modulation.

 

I'd never hesitate to use baluns though. A lot of devices actually have baluns built into them, you just don't realize it.

[shoreviewsecurity 0]

Cool!

 

Thanks again!!

[survtech 0]

Some CAT3 has so few twists you could almost say it has none. The main problem with it is that because of the lack of sufficient twist, it is more prone to noise than CAT5/6/7. You can still transmit video through it but it is much more susceptible to crosstalk from any other signals on adjacent pairs.

[C7 in CA 0]

You can purchase 25-pair CAT5E cables as well but I doubt that is what you are dealing with. Most likely you are looking at 25-pair CAT3.

 

We installed a 25 pair 5e on the job I'm working now. Some of those pairs were twisted way tighter then I have ever seen on a 4 pair 5e.

[3RDIGLBL 0]

This was a couple years back but we did a job that we thought would not work out and after a couple trips to the customers we were successful. He has a long driveway (over 1000') and he wanted a camera at the end of the driveway to try and capture the person destroying his mailbox. We were the only ones bidding as the other businesses they called said it could not be done. LOL! Anything is possible.

 

Anyhow, the only cable they had was a telephone company service cable that had 2 unused pairs. Our first issue was how to get power over 1000' over a single pair and not only power the camera but also the heated enclosure....We accomplished that using a 24V AC source at the house and using a 12V enclosure with a 12/24V camera and a voltage regulator. By george we got it working and it has been for two years and they also got the suspects! The video used a single pair as well and a power balun.

 

This customer only wanted one camera and this is what they wanted it for! They wrote us a great email for the job done and are very happy with it.

[survtech 0]

The biggest problem we found is the relative unavailability of direct burial CAT-5. Even when we did find it, the cost of 25-pair was astronomical. Granted, it is considered not absolutely necessary to use direct burial cable in conduit, but we've found that it is. Outside conduit tends to fill up with water, no matter how much care was taken in its installation. Non direct burial cable typically won't last very long in that environment.

[wisp_engineer 0]

The biggest problem we found is the relative unavailability of direct burial CAT-5. Even when we did find it, the cost of 25-pair was astronomical. Granted, it is considered not absolutely necessary to use direct burial cable in conduit, but we've found that it is. Outside conduit tends to fill up with water, no matter how much care was taken in its installation. Non direct burial cable typically won't last very long in that environment.

 

 

That is correct!

 

Any time you use cable in conduit that is buried you should always use direct bury rated cable with either flooding jelly or some type of waterblock tape or powder. Water WILL find its way into the cable.