Need advice on fibre cables - from house to cabin. DAC? SM / MM? etc.

Forums › LAN (ethernet/Wifi/routers/Bluetooth) › Need advice on fibre cables - from house to cabin. DAC? SM / MM? etc.

timbosan

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#319971 20-Jun-2025 19:42

Hey all, looking for some help on a networking change. I have a Unifi setup and want to connect a switch in the house (US24) to a switch in the cabin (US-8-150) via fibre. Originally I was trying to find one of the Ubiquiti DAC (direct attached cable) - for the 25 meters or so of the run. But then I realised - and this is where I need some help - DAC cable are (as their names suggests) directly connected to the transceiver right? This is a problem as I have to run the cable through conduit. It's 32mm OD but there are 2 90 degree bends, one wide and one small.

So, as I understand it, I need something like this (from fs.com ) - https://www.fs.com/au/products/70220.html and then a cable like this - https://www.fs.com/au/products/70220.html This will let me runt he cable through the conduit and then attach the transceivers on both ends, is that correct?

But even then what options do I go with? LC UPC both ends? What fibre count? And what option for the cable?

Many thanks for any help!!

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#3385814 20-Jun-2025 20:03

I would say you only need 2 x 1Gbps MM optics

Like these - https://techspecs.ui.com/unifi/accessories/1-gbps-multi-mode-optical-module?subcategory=accessories-modules-fiber

and then a 30m one of these - https://techspecs.ui.com/unifi/accessories/uacc-ofc-m2-lulu?subcategory=accessories-modules-fiber

or you could just use an ultra slim copper (RJ45) cable - https://www.pbtech.co.nz/product/CABCXT833000/Cruxtec-Cat6-Ethernet-Cable---30m---White

Your 90 degree bends will cause you problems - you might be better off getting a pull cable run through first before trying to feed any cables first.

timbosan

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#3385816 20-Jun-2025 20:41

gokiwi64:

I would say you only need 2 x 1Gbps MM optics

Like these - https://techspecs.ui.com/unifi/accessories/1-gbps-multi-mode-optical-module?subcategory=accessories-modules-fiber

and then a 30m one of these - https://techspecs.ui.com/unifi/accessories/uacc-ofc-m2-lulu?subcategory=accessories-modules-fiber

or you could just use an ultra slim copper (RJ45) cable - https://www.pbtech.co.nz/product/CABCXT833000/Cruxtec-Cat6-Ethernet-Cable---30m---White

Your 90 degree bends will cause you problems - you might be better off getting a pull cable run through first before trying to feed any cables first.

Thanks! Some good points and I should have said:

* I already have a cat6 outdoor rated cable in the conduit - that will breakout before the cabin into an outdoor switch. Hence the need to run a second cable, and why not go 10 gig!!
* There is a pull-line in there as well (I did try and plan for every situation)

Since I don't really want to do this again in the future, and part of the trench is still open and I really want to cover it cover, can I just use the 10G module https://techspecs.ui.com/unifi/accessories/10-gbps-multi-mode-optical-module?subcategory=accessories-modules-fiber ?

And use the same cable?

gokiwi64

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#3385819 20-Jun-2025 20:53

Do your switches support 10Gbp ?

ANglEAUT

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#3385825 20-Jun-2025 21:26

gokiwi64:

Do your switches support 10Gbp ?

US-8-150W = ❌ No
US-24 (gen1) = ❌ No

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raytaylor

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#3385827 20-Jun-2025 21:29

Multimode fiber is old technology and should never be used to leave a building
Thats any cable that says OM3 and OM4

If you are going between buildings, tenancies or dwellings then you should be using Singlemode fiber.
Its futureproof and equipment for single mode fiber is readily accessible.
Thats any cable that says OS2

The other benefit is that if you ever decide to have a second ONT installed, say if you rent out the cabin, OS2 cable is compatible with UFB fiber networks where as multimode is not.

The name may sound confusing but multimode fiber is less useful than singlemode fiber.

Once you have your chosen switches, such as the unifi models you have, you can just use a duplex OS2 fiber cable (that means two fibers) of an appropriate length, pull it through the duct and plug it in at each end.
Standard patch cables from FS.com work, so long as its secure from rodents inside a sealed conduit, otherwise go with armored patch cables.

The cable ends should be duplex LC-UPC (blue, not green)

I dont believe you can get DAC cables longer than about 3 metres. They are really for just going between switches in the same cabinet.

The cable you have linked to is perfect for the job. We use it for running our antennas on cell towers.
Note both your links were the same.

The cable options to choose are
- Custom Length - make sure you go with more than you need, coil the rest up in an accessible place.
- Fiber Counts: 2 fibers
- Connector A: LC UPC Duplex
- Connector B: LC UPC Duplex
- Pulling Eye: Both Ends
- Packaging: Any option they give you.

The SFP module for each end is
- If both your switches have SFP+ 10g ports https://www.fs.com/au/products/74673.html?attribute=111874&id=4370229
- If one or both of your switches have SFP 1g ports: https://www.fs.com/au/products/75326.html?attribute=5963&id=4189815
I am pretty sure all unifi switches are SFP+ 10gbit

Edit: I am thinking more about this. I am replacing 80mbit radio links around a housing campus at the moment and we are livening it up with 1gbit SFP modules so I could be wrong about all unifi switches being 10gbit. There would be a reason we are only lighting it up with 1gbit and that would be the customer not wanting to replace expensive switches yet until next years budget. Best you confirm the specs.

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gokiwi64

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#3385828 20-Jun-2025 21:37

Not all Unifi switches are 10Gb, many are 1Gb.

MM is definately viable and most definately usable and acceptable, especially over short distances and low bandwidth - absolutely single mode for longer distances and higher bandwidth.

This is not a comercial installation but a residential - it does not need to be expensive or complicated.

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fe31nz

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#3385835 21-Jun-2025 01:31

Just for completeness: DAC = Direct Access Copper - the cables are copper, not fibre. They are normally quite short - the faster the speed, the shorter they are. You can probably get them up to 5 metres long at 10 Gbit/s, but they have to use thicker copper (smaller SWG number) to do more than about 3 metres, so they get a bit bulky and stiff. Definitely not recommended for outdoor use. I have some 5 metre DAC cables for my 40 Gbit/s Infiniband connections, which are made up of 4 cables at 10 Gbit/s each. A bundle of 4 cables is very stiff and the best (most expensive) one I have is about 9 mm in diameter. The cheaper ones are 10 mm.

richms

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#3385858 21-Jun-2025 12:19

The price difference of MM cable being a better buy is gone now. Few dollars only in it.

As you only want gigabit now, you can go and get a pair of gigabit media converters with SM 20km optics in them for about $30 on aliexpress. Power adapters are questionable but the units themselves are fine. Some are SPF modules so you can pop them out and into a switch when you upgrade, and then you are ready to go to 10 or 25 gig when the time arises, but are not overspending on gear now.

Armoured cables pre-terminated are available on there too for excellent prices. Just check that it will pull thru your conduit with the plugs on it, some are staggered lengths to help with that but most are not. The cost of going to a 4 or 6 fibre cable is not much more than a 1 or 2 cable.

Richard rich.ms

timbosan

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#3385862 21-Jun-2025 12:51

ANglEAUT:

gokiwi64:

Do your switches support 10Gbp ?

US-8-150W = ❌ No
US-24 (gen1) = ❌ No

Good point, not currently, but I don't want to limit myself to 1Gb and then need to change when I update my switches

timbosan

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#3385864 21-Jun-2025 12:53

fe31nz:

Just for completeness: DAC = Direct Access Copper - the cables are copper, not fibre. They are normally quite short - the faster the speed, the shorter they are. You can probably get them up to 5 metres long at 10 Gbit/s, but they have to use thicker copper (smaller SWG number) to do more than about 3 metres, so they get a bit bulky and stiff. Definitely not recommended for outdoor use. I have some 5 metre DAC cables for my 40 Gbit/s Infiniband connections, which are made up of 4 cables at 10 Gbit/s each. A bundle of 4 cables is very stiff and the best (most expensive) one I have is about 9 mm in diameter. The cheaper ones are 10 mm.

Good to know - especially the "not recommended for outdoor use"!. FYI this is what I was originally looking at https://store.ui.com/us/en/category/accessories-modules-fiber/collections/accessories-pro-direct-attach-cables/products/10gbps-direct-attach-cable in a 20m length (which would have been just long enough)

timbosan

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#3385865 21-Jun-2025 12:54

raytaylor:

Multimode fiber is old technology and should never be used to leave a building
Thats any cable that says OM3 and OM4

If you are going between buildings, tenancies or dwellings then you should be using Singlemode fiber.
Its futureproof and equipment for single mode fiber is readily accessible.
Thats any cable that says OS2

...

Excellent, just the info I need :-) Thank you

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Spyware

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#3385969 21-Jun-2025 14:26

https://www.fs.com/au/products/88529.html?attribute=714&id=1090112

and 2 x https://www.fs.com/au/products/75326.html?attribute=5963&id=4189815

Spark Max Fibre using Mikrotik CCR1009-8G-1S-1S+, CRS125-24G-1S, Unifi UAP, U6-Pro, UAP-AC-M-Pro, Apple TV 4K (2022), Apple TV 4K (2017), iPad Air 1st gen, iPad Air 4th gen, iPhone 13, SkyNZ3151 (the white box). If it doesn't move then it's data cabled.

fe31nz

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#3386091 21-Jun-2025 23:23

timbosan:

Good to know - especially the "not recommended for outdoor use"!. FYI this is what I was originally looking at https://store.ui.com/us/en/category/accessories-modules-fiber/collections/accessories-pro-direct-attach-cables/products/10gbps-direct-attach-cable in a 20m length (which would have been just long enough)

That page is a bit misleading. The text says DAC, but if you click on the "10G" button and then on the various length buttons in order, you see pictures of DAC cables for up to 3 m (thicker black cables), but above that the pictures seem to show optical fibre cables (thinner and aqua coloured).

richms

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#3386179 22-Jun-2025 11:56

fe31nz:

That page is a bit misleading. The text says DAC, but if you click on the "10G" button and then on the various length buttons in order, you see pictures of DAC cables for up to 3 m (thicker black cables), but above that the pictures seem to show optical fibre cables (thinner and aqua coloured).

Its still a direct cable. Some places call them active optical cables but its basically just getting you the worse of both worlds stuck together. Chunky plugs and fragile fibre cable. Also when the electronics die you have to replace the whole thing. Stupid idea but I guess some people want them.

Richard rich.ms

timbosan

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#3386804 24-Jun-2025 17:19

Hi all, just to close out this thread, I put everything from fs.com in my cart, changing the transceivers to 1Gpbs and the cable to armoured, then found its cheaper and quicker to get it from gowifi.co.nz :-)

https://www.gowifi.co.nz/fibre-optic-cables/fc-sm-100.html
https://www.gowifi.co.nz/fibre-modules/uacc-om-sm-1g-s-2.html

Many thanks to everyone for their help!

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