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Old 07-07-2015, 10:27 PM   #1
Registered: Nov 2007
Location: CT
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help with fiber optic: single multi mode 50 62.5 and connectors

need some advice, i know just enough to be dangerous with fiber.
my environment has a fiber patch panel that has over 20 runs coming into it and they are ST connectors. So for each network run there's 2 ST connectors in the panel, an A and a B.
On the other end of those runs are ST connectors as well, an A and a B.

I'm in the process of doing new switches on each end of the fiber run. the switches are gigabit and have 4 SFP ports (i'm only using one for now). I'm using the inexpensive multimode Cisco SFP's that use an LC connector.

From the switch at each end to the computers I'm using cat5e or cat6 cable. I'm pretty good at putting RJ45 connectors on the end of the cables if need be, and for 95% of the time going from the network switch to computers it's going to be copper RJ45 cat5/6. But for a few high end servers i have the option of doing fiber right to them (in addition to copper cat 5/6).


a) how hard & expensive is it to terminate the ends of fiber optic with connectors? in my case it would have to be ST and LC connectors.

b) I'm stuck with ST connectors with that existing infrastructure. Was my choice good going with an LC connector on the switch side?

c) i need fiber patch cords from my patch panel to the switches in my rack. It is an ST connector in the panel going to an LC connector into the SFP in the switch. length between 3 to 6 feet, or not more than 2 meter. If i just buy them mail order I'm guessing that's probably the best way? ... do i get 50/125 or 62.5/125 ? can someone explain the difference on this and what i should order for patch cords?

d) for single mode vs multi mode, and having a patch cord with an ST connector (A & B) on one end and an LC connector on other which has 2 ends, that isn't "single mode" on each A and B side is it? i'm kinda confused on single mode vs multi mode and what's actually happening.

e) i'm stuck with using existing fiber runs, but if you had to start from nothing and kept cost in mind how would you do it? Let me know what you would chose for connector types on the end of the fiber cable. I went with gigabit switches and not 10gig switches because of cost, last i checked 10gig was pretty expensive.
Old 07-07-2015, 11:15 PM   #2
Registered: Aug 2002
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a) If you have to ask then I would buy the cables already assembled.
b) I really do not have a preference but yes.
c) Yes buy is the best way see answer a. The cables have to match the switch. It is the size of the core/cladding in um.
d) You can find the answer by a quick google search. If everything matches per question c then your ok.
e) Never really had to do anything from scratch yet so I have not thought about it much.


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