cant the x450-g2 sync up at 100mbps fiber on the sfp port?

  • 2 June 2020
  • 4 replies

Userlevel 1

Hello.  We have an ATM machine in a hospital campus that is too far for Ethernet.  It’s been connected using a TP-Link 100mbps fiber optic media converter for years.  The other end is the same 100mbps grey box into a Cisco switch.

Now the connections are terminating to a new facility within the Hospital.  Our new facility has the X450-G2.  Rather than move the TP-Link box to that rack, across campus, I’d rather not have additional “junk” hanging off the switch.  So I checked the TP-Link specs and it’s 1310nm SM FDX fiber.  So I purchased an appropriate 1310nm 2km SFP and put it in the extreme switch.  When I went to swing the cable over from the old feed to the new one that our cabling vendor ran, I got about -11dB signal according to show port 1:51 transceiver command.  So physically for 100mb that’s a decent optical level.  However the port never transitioned to an active / up state, and the TP-Link device link light did not illuminate, even after power cycling it.


So long story short, can’t the X450-G2 Poe sync up at 100meg FDX if the SFP is designed for it?  

I’ll likely get a different media converter (1gbps) and SFP to match instead. has media converters with SFP sockets on them so you can customize the optics.  I’ll likely go with that.

4 replies

Userlevel 6

I feel like the question may be obvious, but I don’t see the answer in your blurb up there. Did you ensure that autonegotiation was on, or the port was hardset for 100/Full?



Userlevel 1

I tried setting port 1:51 to 100 full.  It kept saying that hard coding the speed was unsupported for the sfp ports (1:49-52, 2:49-52).

The same commands to specify the speed on a copper port don’t seem to take on the SFP port.

I just ordered gig optics and’s 10/100/1000 copper to sfp media converter.

When I get back to that site I’ll have to see if that’s the problem.  I almost think EXOS see’s SFP and only allows that to run at 1 gig, or it see’s SFP+ and only allows that to run 10gig (at least in this switch model).


Userlevel 4

X450-G2 allows 100 Mbit/s SFPs.

  • Which SFP Module did you get exactly? 100Base-SX or 1000Base-SX?
  • Do you have Singlemode or multimode cabling? “1310nm 2km SFP” speaks for Multimode cabling, but “1310nm SM FDX” for Singlemode.
  • Did you try swapping the receive and tranceive fibers with each other at one end?
Userlevel 1


The cabling vendor of the hospital installed armored single mode fiber.  Its a requirement of the hospital.

I thought 850nm was MM and 1310 and higher was SM.  Anyway we have two locations in this hospital.  The X450-G2 has 2 1gbps 1310nm 2km SFP connected to 2 cisco 1310nm 2km SFP in the other location.  The link is up.

Didn’t see a need to swap recieve and transmit fibers at my end because I was monitoring the port on the EXOS side and it saw light at -11 db.  When unplugged it was inf* (infinate).  It def. saw light.

I just received a new media converter and sfp for it as well as another sfp for the exos side, this time 1gbps 10km transmitter.

Just to make sure it wasn’t DOA, I tried it at home (though I have a Ubiquiti Unifi switch) and it linked up fine. 

In the next week or two I will visit the site and try with 1 gig optics instead of 100meg optics.  I know the 1 gig optics work fine for our other trunk link throughout the hospital campus.