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New Member

type of fiber for zx sfp

hi, i have the following problem:

i cannot get a zx sfp to come up. i was wondering if you guys could provide the right fiber to use with a back-to-back zx sfp setup.

at the moment we're using 9/10 single mode fiber and they won't come up.

we've used the right attenuators and even a power meter and see no light coming out of the sfp. we even tried lx sfps and they do not come up either. we even tried a small fiber loop that i borrowed from cisco local office and that did bring up the interfaces.

but the thing is, i'm confused:

can either an lx or an zx sfp come up when using sm 9/10 fiber? (with the same fiber).

if not, shouldn't the lx come up?

any ideas?




Re: type of fiber for zx sfp

Well first of all if you are going to be connecting these routers or switches up back to back I would not be using the zx series. Stick with the lx because those are designed for shorter distances and they TX at a range of -3 to -9 and RX at -3 to -19. It seems that they make a MM and a SM version of the LX/LH card. I would try to find out if yours if MM or SM, if MM use the obvious and if SM than 9/10 will be fine along with the ZX SFP. One other thing with the LX is that you might need to insert a mode conditioning patch cord it the mix too. Another thing is that you can't mix and match the cards either, it should be an lx to lx or zx to zx. You are definetly having problems though if you are not seeing any light come out of the SFP, ensure you have your gear set to the correct wavelength to measure it properly. It will be 1300 for the LX and 1550 for the ZX. With the cable you used from cisco, did it work for both the LX and ZX SFP's? I hope this helps a little bit.

New Member

Re: type of fiber for zx sfp

that part about the lx being mm or sm i did not know. i will see if i can find any mm fiber.

the distance will be around 18km, that's why we're using the zx's, but we wanted to try'em out first. and since that did not work and we tought the zx's were broken, we tried the lx's with the same results. (we never mixed lx with zx).

the power meter has been tried will all posible wavelenghts, no luck.

but the weird thing is this magic fiber loop i borrowed from cisco, which makes everything come up.



Re: type of fiber for zx sfp

It sounds like bad fiber patch cables, if you're getting no optical power detected at all on the meter. You know the SFPs work.

What's "magic" about the loop you borrowed from Cisco? Did you patch your cables into that Cisco cable? Or did you use just Cisco's cable to connect the two SFPs directly? Or was it a loopback that took the TX signal from the SFP and fed it back into the RX port of the same SFP?

Also see my response to your other post, regarding checking for proper cross-over.

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