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We have a fiber switch (pic below) We need to run another fiber switch in another area of the building. We are going to use LC cable as is the same in the 9F port. I see there is a SFP to LC adapter. The network person we had just left. What type of adapter is it? I assume it is something like this:

https://www.amazon.com/TRENDnet-Multi-Mode-Mini-GBIC-Compatible-TEG-MGBSX/dp/B0009JR5SM/ref=pd_bxgy_147_img_3?_encoding=UTF8&pd_rd_i=B0009JR5SM&pd_rd_r=SB9YQ77HY9KN52M08JKM&pd_rd_w=kpQgc&pd_rd_wg=LnzrG&psc=1&refRID=SB9YQ77HY9KN52M08JKM

Does it matter what type exactly I get? I see a lot of different ones.

enter image description here

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Short Answer:
My best guess from the context you've provided so far is that you're on the right track and it's 1Gbps 1000BASE-SX over 50µm multimode fiber thus having a 550m range, meaning the TRENDnet TEG-MGBSX is compatible. But it's hard to know for sure without reading the specs of that existing SFP module and the fiber optic cable.

Long Answer: There are lots of considerations in modern fiber optic Ethernet connections:

  • Speed? (1G, 10G, 40G, 100G?)
  • Ethernet protocol (IEEE 802.3 1000BASE-SX? 1000BASE-LX? 10GBASE-something? others?)
  • Connector type (LC? SC? others?)
  • Fiber type (single-mode? multi-mode? diameter?)
  • Distance it needs to go (100m? 300m? 500m? 1km? 10km?)

Some of the choices on the list above constrain your other choices, but some are mix-and-match.

This is all to say that just because you see that an existing connection uses LC connectors in an SFP module, it tells you almost nothing about what flavor of Ethernet it's using, what kind of fiber it's using, what wavelength of light it's using, how fast it goes, or how far it can go.

I recommend you use the management capabilities of that switch to see what that SFP module identifies itself as. Or, if you can afford to bring that link down briefly, unplug the module and quickly take a picture of its label(s) and then plug it back in.

Yes, it matters what type of LC-connector SFP module you get. All of the ones that have distance ratings in kilometers are based on 1000BASE-LX over single-mode fiber, which is probably completely incompatible with what you're using for in-building links. Anything rated in hundreds of meters is 1000BASE-SX over multi-mode fiber. Ignore the 10 Gigabit stuff that requires SFP+ unless you can verify that your equipment has 10 Gigabit SFP+ receptacles (SFP+ is the 10 Gigabit version of SFP; if something is SFP without the plus, it only does 1Gbps, not 10Gbps).

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  • Okay, I think that will work for now. With the 10gb ones I see they are about $100 more in price. I do not see using more than 1gb in the next few years. Is that correct in what I am saying? The fast the more expensive. We are ordering this cable lanshack.com/… about 200feet of it with LC connectors. Not sure what is going on the other side yet. Maybe the same switch maybe something else if we already have one. I have to look. Feb 26 '18 at 22:44
  • I am going back there on Thursday. I will pull the old adapter and take a picture of it then. I wanted to do that today but did not want the network to go down. Feb 27 '18 at 3:05
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The SFP to LC adapter you are referring to is a transceiver - it provides the optics and electronics to connect the fiber to the switch.

From what can be extracted from the photo:

  • fiber jacket color (aqua) indicates OM3 multi-mode fiber (MMF)
  • SFP bail type and switch markings indicate gigabit speed

my guess is also a 1000BASE-SX type transceiver. The exact type of the switch and possibly the port status for the fiber port could do much to verify that.

Depending on the policy the switch manufacturer is going by, either any generic SFP module works or just "original" ones. (The switch can talk to the module and check its brand.)

Usually, you don't really have to buy genuine transceivers but there are many vendors selling compatible ones which can be much cheaper and often are of the same quality. Original -SX transceivers may cost as much as $200 while compatible ones usually go for $25. Again, you'll have to know the make and possibly type of your switch to buy a compatible part.

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  • Thanks for that. I will probably just pull the transceiver from the 9F port and buy the same one. For the switch bough on the other end of the cable. I found this one amazon.com/gp/product/B01NBBA1HQ/… with has an attached transceiver to buy for about $15 so i will probably order that one for the new switch. Feb 28 '18 at 1:38

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