Solved: 100base fx - 100base lx compatibility

davmetcalf · ‎08-08-2018

I have a device to which I need to connect a catalyst switch (2960XR). The device has a 100base fx interface which they state as capable of running over single mode fibre. The vendor of this device has suggested connecting it to a SFP that supports 100base lx over single mode (G652) will work. However I can find no information that supports this. I looked at the 2015 IEEE Ethernet standard and I can only find a statement regarding fx over multimode. Although the fx and lx optical characteristics look similar I am not sure they are the same and not sure therefore that they will work together reliably. Are there any references that can assure me that the two standards will work together over single mode?

Leo Laohoo · ‎08-09-2018

@davmetcalf wrote:

we only have SMF (already installed). I am assuming therefore that they MMF SFPs can't be used (let me know if that's incorrect).

That is correct. Always use the same wavelength.

@davmetcalf wrote:

The issue is the interoperability of 100base lx (which we can get SFPs for) and 100base fx. which the vendor is telling me is OK but he can supply no justification.

LOL. Typical. I suspect the vendor doesn't even know what "lx" or "fx" means.

Please make sure the equipment really has 100BaseLX modules.

View solution in original post

Leo Laohoo · ‎08-08-2018

Transceiver Module (TMG) Compatibility Matrix

(Thanks to Marvin for showing me this link.)

davmetcalf · ‎08-09-2018

Hi Leo

Thanks for responding. Apologies, I should have also said that I looked at the matrix and the SFPs for 100base fx all state the media should be MMF and we only have SMF (already installed). I am assuming therefore that they MMF SFPs can't be used (let me know if that's incorrect).

The issue is the interoperability of 100base lx (which we can get SFPs for) and 100base fx. which the vendor is telling me is OK but he can supply no justification.

At the moment I'm telling him to replace his equipment as he had the spec but apparently decided to ignore it. However I thought I'd ask if I'm wrong to do so.

Regards

David

Leo Laohoo · ‎08-09-2018

@davmetcalf wrote:

we only have SMF (already installed). I am assuming therefore that they MMF SFPs can't be used (let me know if that's incorrect).

That is correct. Always use the same wavelength.

@davmetcalf wrote:

The issue is the interoperability of 100base lx (which we can get SFPs for) and 100base fx. which the vendor is telling me is OK but he can supply no justification.

LOL. Typical. I suspect the vendor doesn't even know what "lx" or "fx" means.

Please make sure the equipment really has 100BaseLX modules.

davmetcalf · ‎08-09-2018

Thanks Leo.