Splicing CAT6 cable?  IP cams, serial comm, etc.  - Page 1
Forum section: electronics / general

author: viper
author_rank: Regular Contributor
timestamp: October 18, 2024, 10:56:00 pm
content: I am having to both rewire some parts of a proximity card reading system that uses RS232 communication, as well as running new cable for IP/POE security cameras. The place is big and I don't yet have a handle on where the NVR will be just yet but I must get some cables into some conduit for now.To the point, it would really help me to be able to cut the CAT6 cable for the cameras once in the building, and run more cable to it later, which will be another large run that I don't want to do right now. Is there a best practice and product for doing CAT6 splicing? Will be degrade signal of say 4K cameras? I've literally seen people hack cables with wire nuts. I'm looking for a pro approach.

author: Whales
author_rank: Super Contributor
timestamp: October 18, 2024, 11:51:00 pm
content: What do you mean by splicing? Joining two cables (extending) or joining 3 (tee)?There are many ways of doing CAT wiring that "work" sometimes, but they can also cause you a lot of frustration trying to debug later when things don't work reliably.Quote"degrade signal" suggests you are thinking about this like analog video cabling. Bad analog cabling will degrade your images gracefully.Digital packet-based signalling (like what is done over ethernet) does not work this way. There is a lot of tolerance, but once you go past a threshold it all goes to crud (big video glitches, video freezing, video dropping out entirely).4K footage is a lot of bandwidth, you are not going to want to cut corners here. If you were pushing SD video over ethernet then yeah you might get away with cutting a lot of corners, but 4K is going to be lot more data then the old analog cables carried. You cameras should specify approximately how many megabit/second they need (note megabyte vs megabit).The correct (quality, reliable) way to do things is to:- NEVER do tees. Each cable has two ends and nothing more.- Ideally have one (big) main POE switch that has an ethernet cable going to every camera. Simple andmost of all easy to debug(each port has lights to tell you if something is wrong with the camera or cable)- If you absolutely can't run cables like that then draw some diagrams that use a few smaller switches around the place. They will need power (some can daisy-chain onto POE, but that gets more complicated and I have not tried it)- Terminate every cable either in a keystone or 8P8C plugAllowing for tees was a thing in older ethernet standards, but it rapidly became a bandwidth and reliability wall, so it has not been done for decades. Itcanwork but it depends on exactly what devices are plugged in, cable lengths and what packets they are sending. I suspect sec cams will shit the bed if multiple are trying to send 4K video streams on the same single cable. Please don't do this.It's possible to get away with joining network cables using wire-nuts, but it will degrade the signals and break the CAT spec. It may work, it may not. It might stop working at night when you need it the most. Stick to the recommended max distances & connection methods and you will get reliable performance.

author: Whales
author_rank: Super Contributor
timestamp: October 18, 2024, 11:55:21 pm
content: Quote from: viper on October 18, 2024, 10:56:00 pmYeah do whatever with wirenuts for thatHopefully it's over short distances, RS232 isn't the best for long range. CAT cable is convenient and good quality for short runs of this.QuoteHey wait, is this for your own personal house or is this for someone else? If you're doing it for someone else then you really need to get the advice and help of whatever equivalent you have to a "registered cabler" over there.

author: nctnico
author_rank: Super Contributor
timestamp: October 19, 2024, 12:15:13 am
content: The pro approach would be to have the cables as a single run.Maybe this is an option:It is a CAT6 junction box but you'll need the right tooling for pressing the wires into the IDC slots (punch down). There are various types of punch-down connectors and each requires a specific tool in order to make reliable connections. The junction box from the pictures appears to have LSA type punch-down blocks so it would require an LSA punch-down tool.

author: Whales
author_rank: Super Contributor
timestamp: October 19, 2024, 07:36:38 am
content: Few more tips:1. Punching down into a keystone is easier than crimping on an 8P8C (RJ45) connector. The punchdown tools are pretty cheap.2. When crimping 8P8Cs onto cables: don't use cheap greymarket crimps. The metal pins are thinner (get jammed in crimping tools :'( ) and their plating is garbage (bad contacts after a short time). Pay the money for good quality crimps, and test them with your tools before buying lots of them.3. When crimping 8P8Cs onto cables: get the right type of crimp for your cable. Use CAT6 crimps for CAT6 and CAT5 for CAT5. Using the wrong crimp can sometimes work, but it's super super frustrating to do (nothing fits quite right and sometimes the crimp fails). Even though the differences in wire and insulation diameter seem insignificant to your bare eyes it makes all the different in the world in practice.4. Watch some videos on the web of how to do the crimping properly. It's not easy to do right when you're starting out.

author: viper
author_rank: Regular Contributor
timestamp: October 19, 2024, 03:24:47 pm
content: thanks guys! This would be the joining of two cables. Not trying to 'tee' or anything. The main issue is right now I do not have a finalized design for the POE cam circuits. We are working on switchers, backbones, etc.It really sounds like I should just toss some mule tape in the conduit with my other pulls, and pull this part of the CAT6 when we have this figured out. I just always trying to pull cable inside conduits with cables already in them. I've had that go bad and you get to pull everything out.I am still doing some learning on POE switches.

author: MarkF
author_rank: Super Contributor
timestamp: October 19, 2024, 03:34:09 pm
content: Depending on where you want to put the splice, why can't you just use aRJ45 Female to Female Indoor Network Coupler? I use a few in my cat-5 runs. But only in accessible places like a utility closet or open basement areas.

author: nctnico
author_rank: Super Contributor
timestamp: October 19, 2024, 03:41:12 pm
content: Quote from: MarkF on October 19, 2024, 03:34:09 pmThe downside is that RJ45 connectors tend to give contact issues when used for a long time so I would not use these couplers to extend cables which need to be in service for 20+ years.

author: viper
author_rank: Regular Contributor
timestamp: October 19, 2024, 04:20:18 pm
content: Would there be a down side to solder and glue shrink? I know it is a little more work, but I would think it would be the best as far resistance. I am just not sure if untwisting causes issues.But yes, any splice ever made will be accessible. My goal is really to take the continuous cable directly to a POE switch.

author: nctnico
author_rank: Super Contributor
timestamp: October 19, 2024, 04:59:01 pm
content: If you need a connection which lasts decades, then a good quality punch-down connector will be better compared to soldering. Solder joints tend to fall apart after 15 to 30 years. An alternative would be to use crimp splices with some heat schrink over them. But it could degrade signal quality which could become an issue if you want to use the cables for 10Gbit.

author: tooki
author_rank: Super Contributor
timestamp: October 19, 2024, 05:26:31 pm
content: Quote from: Whales on October 18, 2024, 11:51:00 pmTees/Y-splitters have never been supported by any of the twisted-pair Ethernet standards. (It was the norm with 10BASE2 “thinnet” over RG-58 coax with BNC’s, though.)Some companies have made daisy-chainable twisted-pair Ethernet tees (or cards with two daisy-chainable jacks) which are simply a little 3-port hub inside. And then there are the “splitters” for 10/100 Ethernet (but not gigabit and beyond!) that leverage the fact that 10/100 Ethernet use only 2 pairs, but jacks are normally wired with 4-pair cable, so you’d use pairs of these “splitters”, one on each end of the cable, to put two distinct 10/100 links through the same cable, one splitter to merge them, the other to separate them again. Gigabit and beyond use all 4 pairs and cannot be thusly combined. (2-pair gigabit existed briefly as 1000BASE-TX, but it flopped and is not used anymore. There’s also a short-distance single-pair gigabit for automotive and industrial use.)Splicing together multiple twisted-pair Ethernet wires simply won’t work.

author: tooki
author_rank: Super Contributor
timestamp: October 19, 2024, 05:31:07 pm
content: Quote from: viper on October 19, 2024, 04:20:18 pmYes, untwisting absolutely causes issues. If you splice with solder, then you want to do it so that the twisting is preserved, with minimal change to the spacing of the wires in a pair. (Space between pairs doesn’t matter.)A common source of poor performance in Ethernet is when an unknowledgeable installer untwists several cm of wires to make it easier to terminate a wall jack.