help a fiber dummy with connections

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sspeed

New Member
May 18, 2017
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I had to tear down my "network closet" over the weekend because I had an HVAC duct separate, that was fun. I thought it would be a good time to make things nicer and more organized.

At the location of my rack I have an incoming fiber connection from my work desktop to the Unifi switch SFP+ port. Been so long since I did that and I don't remember it all, but I have:

Finisar FTLX8571D3BCL 10GBASE-SR/SW SFP+ Transceivers

Total Cable Solutions OM3 10Gb 50/125 Multimode Duplex Fiber Optic Patch Cable, LC to LC (15 Meters)

For my ESXi servers and the Synology I'm using:
SFP-H10GB-CU3M CISCO SFP+ TWINAX COPPER CABLE 3M PASSIVE DAC CABLE

Those run into a Mikrotik switch, which also uplinks with the same type of cable to the Unifi switch.

Anyway, I'd like to have the front of the rack using just patch cables, vs running them from the back up to the switch, but running into some problems on how to do that. I see RJ45 has passthrough keystone jacks that you can just plug into a keystone patch panel, but the only keystone jacks for 10g I see are LC keystone jacks? Dumb question, but there is probably no such thing as an SFP+ passthrough keystone jack for DAC cables?

So I'm guessing what I need to do is:
Transceiver at desktop -> OM3 fiber cable -> LC keystone jack in patch panel -> shortish OM3 cable from patch panel to switch -> Transceiver in switch

Give me ideas, I don't even know enough to be dangerous. :)
 

LodeRunner

Active Member
Apr 27, 2019
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I've never seen a DAC keystone, given length limits of DACs I can't imagine anyone making one (nor how one would fit a DAC perpendicularly in an interior 3.5" wall gap without crushing it). I think you're going to just have to live with the DACs as is, unless you want to go ahead and replace them with LC transceivers.

Edit: I suppose one could design a bulkhead connector where the interior side of the wall fitting has the DAC at an angle and the exterior face is straight in, or also at an angle, but how the DAC ends in the middle would be powered is not a question I can answer.
 

ArmedAviator

Member
May 16, 2020
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Kansas
There are no Direct-Attach-Copper (DAC) keystones. It would be more complicated than simple electrically linking the pins.

You can either go with the LC keystones and appropriate fiber patch cables OR run the DAC through an empty keystone hole and call it good.
 

DinoRS

New Member
Jan 17, 2020
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4
3
do something like this instead:

Desktop -> LC Fiber Cable -> Fiber Wallmount box with LC -> MTP/MPO Keystone Module -> MTP/MPO Cable to Cable strain relief (f. ex. another Fiber Wallmount box next to the Patch Panel) -> MTP/MPO Cable from strain relief to MTP/MPO-> LC Keystone Module in Patch Panel -> LC Cable to Optical Transceiver on the Switch

believe me you want to convert between LC -> MTP/MPO because I've just gone through getting some LC Fiber onto the keystone modules in Fiber Wallmount boxes and since the LC Connectors are so big it's anything but fun to get them placed nicely without potentially damaging the Fiber cable.
Still have to check if mine work but I'm seriously considering ordering replacement LC / MTP/MPO Keystone Modules + OM5 MTP/MPO Cable even if it works because it's so ugly to handle overall. I'd expect DACs to be even worse to handle so even if you could make your own Keystone Mount for DACs I'd strongly advise against it.
Other things to note:
- Conventional patch panels don't provide cable strain relief for Fiber Optics, if you intend to use a conventional patch panel and make it work with the Fiber cables, you should strongly consider adding another strain relief (Fiber Wallbox) nearby the patch panel.
- if you would ever intend to patch fiber runs through your patch panel don't forget your bend radius of minimum 40 mm that means only something like Port 1 -> Port 6 on the patch panel would work, Port 2 -> Port 3 on the patch panel would be a too tight radius. Ofcourse you can use 2 & 3 to connect to your switches etc. just keep in mind if you intend to do something like that you need space between Ports on the Patch Panel, too.

Might ask if I may take a few pictures without further explanation (yet) how things could look like.
 
Last edited:

sspeed

New Member
May 18, 2017
7
0
1
52
do something like this instead:

Desktop -> LC Fiber Cable -> Fiber Wallmount box with LC -> MTP/MPO Keystone Module -> MTP/MPO Cable to Cable strain relief (f. ex. another Fiber Wallmount box next to the Patch Panel) -> MTP/MPO Cable from strain relief to MTP/MPO-> LC Keystone Module in Patch Panel -> LC Cable to Optical Transceiver on the Switch

believe me you want to convert between LC -> MTP/MPO because I've just gone through getting some LC Fiber onto the keystone modules in Fiber Wallmount boxes and since the LC Connectors are so big it's anything but fun to get them placed nicely without potentially damaging the Fiber cable.
Still have to check if mine work but I'm seriously considering ordering replacement LC / MTP/MPO Keystone Modules + OM5 MTP/MPO Cable even if it works because it's so ugly to handle overall. I'd expect DACs to be even worse to handle so even if you could make your own Keystone Mount for DACs I'd strongly advise against it.
Other things to note:
- Conventional patch panels don't provide cable strain relief for Fiber Optics, if you intend to use a conventional patch panel and make it work with the Fiber cables, you should strongly consider adding another strain relief (Fiber Wallbox) nearby the patch panel.
- if you would ever intend to patch fiber runs through your patch panel don't forget your bend radius of minimum 40 mm that means only something like Port 1 -> Port 6 on the patch panel would work, Port 2 -> Port 3 on the patch panel would be a too tight radius. Ofcourse you can use 2 & 3 to connect to your switches etc. just keep in mind if you intend to do something like that you need space between Ports on the Patch Panel, too.

Might ask if I may take a few pictures without further explanation (yet) how things could look like.
Thank you, that's very helpful. I would definitely appreciate some pictures if you have them.