Switches with MT-RJ FX Ports

What type of cabling do I need to connect two switches with FX ports?

For example, two Cisco 3550-24-FX switches.

I know you use fiber cables with mtrj connectors. Do they make a crossover version of these? I heard you can change the polarity but most information online is confusing.

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Comments

peanutnoggin

In my home lab, my 3550 has 2 FX ports. I use the GBIC with SC connectors. In addition to that, we have a couple of 3550-24FX at work that are all MTRJ. So it really depends on which 3550 you are talking about. HTH

-Peanut

DPG

Cisco WS-3550-24-FX-SMI

24x 100base-FX MT-RJ
2x GBIC

peanutnoggin

DPG wrote: »

Cisco WS-3550-24-FX-SMI

24x 100base-FX MT-RJ
2x GBIC

Okay... so with that switch... you'll use a normal fiber multimode patch cable. I would recommend getting the GBICs and using the 2 Gig ports as an etherchannel to another switch if you can with SC fiber cables. But to answer your original question, there is no fiber "crossover" cable that I'm aware of... HTH.

-Peanut

DevilWAH

you don't need a cross over fibre cable...

more fibre works of a pair of fibres, (each port on the switch send the transmit information down one of the fibres and listens for data on the other), and because its just one pair, at either end of the fibre you can flip the connector over. so in effect change it from straight through to crossover (all you are doing are making sure the TX ports match with the RX ports at either end). you often find that the person who spliced the intermidate fibre will have flipped there pair over by accident, so it can be a case of tried both ways to get it to work.

now you have the 24 fx smi switch that as people have mentioned has 24 mt-rj ports and 2 gbics. one thing to remember is that gbic can only run at 1gig speed, and the MT-JR posts can only run at 100mb, they are also multi mode fibre only....

bearing that in mind you can't connect a MT-JR port to a GBIC port on another switch no matter what GBIC module you purchase.

you either need a switch that can support 100mb multimode fibre at the other end, or do what I did and got a ethernet to fibre converter, plugged my standard 3550 switch in to that to give me the 100mb fibre port i needed.

to connect two FX models together you have two options, use the GBCS or the MT-RJ's,

GBIC modules can be single or multi mode fibre and give you a 1gig link, but as you only have two you may want to use them for you core links. as mentioned before the MT-JR's are multi-mode only.

as for what patch leads you need it depends what you have in-between.

direct switch to switch would be MT-JR to MT-JR multimode patch lead.

other wise it is what ever the connection is in-between. Multi mode is often terminated with SC connections but there is also ST and LC (among others), a quick google with let you know what you have. there different enough to easily see in a photo.

Fiberr patch leads don't care what why round you are connection them you just need to know the connection at either end and the type of fibre (multi or single mode). And lastly there are two types of multy mode. 50/125 and 62.5/125 (the inner and outer core diamators in microns). you want the same for all links in the fibre between two switches, the MT-JR ports will work with both types of multi mode, but ideally like I say stick to one throughout (over short distances a mixture may well work but it is far from ideal)

any other questions let us know.

DPG

DevilWAH, thanks for the great explanation.

I have worked in a NOC for almost 4 years and have yet to see a MTRJ cable. I now know I just need a regular patch cable to connect the switches via the MTRJ connectors.

Netwurk

Look for SC to SC Multimode Duplex 62.5/125 Fiber patch cables