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Problems Connecting two Cisco 2950 with a fibre link.

Problems Connecting two Cisco 2950 with a fibre link.

Problems Connecting two Cisco 2950 with a fibre link.

Hi every one,

I have two Cisco Catalyst 2950 Series (24 Ports each) both are 10/100 switches.
We currently have a fiber link between two buildings.(building1 & building2)where building 1 is the main building.
The two switches don't have a fiber adapter.
I was advised to buy the following:

2 x Startech Media converter (1Gbit)
2 x LC-ST Patch cable

I was told I need one at each switch to convert the fibre back to standard Cat5.
in building 1, I connected a CAT5 cable into 1 Startech Media converter and then plugged a LC-ST Patch cable Into the media converter, and then into the wall outlet. then I did the same thing in building 2.

I linked the cisco switch in building 1 to our main network switch using a CAT5 cable.

everything looks like is conected properly. (I say it looks because when i connect something to port 3 in the wall, the port 3 in the swicth in building 2 goes green and also goes green in building 1)

I get green lights when i connect a device (laptop) in one of the wall sockets in building 2 but I dont get connection to the network. so i guess the problem is in building 1?

I was told by the manufacturer company that it was because my switches are 10/100 and the converter is 1gbit and that I had to get a 10/100 converter because converters dont negotiate speed.

before i go and buy another two converters can you please tell me if there is anything I can do?

I heard about accessing the CISCO switches to configure them but I have not done this before.

Many Thanks

Let me know if you require more information.  

RE: Problems Connecting two Cisco 2950 with a fibre link.

First is the media converter's FX LED on or blinking? If not swap the RX and TX fibers on ONE end. If this LED won't light you likely have a fiber problem.

Second is the media converter's TX LED on or blinking? If not there is a problem with your connections to the switch. Options include swapping patch cords or going into the switch's configuration and forcing it to different configurations (speed and duplex) to try and find a common setting that will work between the media converter and switch. Also try the full/half duplex switch on the media converter and see if that makes a difference.

Finally according to the spec sheet for the StarTech Gigabit Multi Mode Media Converter (LC/SC-550m) ET91000LC / ET91000SC found here us.startech.com/media/products/et91000sc/manuals/ET91000SC.pdf this device may only support 802.3 1000Base-TX on the copper side. Why get gigabit converters for 10/100 switches?

Another option is to get a pair of switches that support gigabit. I have used a bunch of Dell PowerConnect 3024 switches. They are easy to manage via a web interface and currently less than $50 on eBay.

Good luck!


RE: Problems Connecting two Cisco 2950 with a fibre link.

Hi wires, thank you for the information.

the PWR and the Full are the only lights (ON) in the converter, the FX, TX, LBT, LLF are OFF.

I think that if the TX, FX is not green or blinking is because there is nothing going through. am I right?

Looks like is not getting any data from building 1 and the the cisco switch in building 1 is not getting anything from the main network switch.

The reason why i am using two 10/100 switches is because the new building only has 3 users . the 1gbit converter was just recomended and sold to me by the people in the shop.

I spoke to them and now they are recomending a 10/100 converter (AT-GS2002/SP) and a module (AT-SPFX/2) to put in the switch

How can I force different configurations on the switch?



RE: Problems Connecting two Cisco 2950 with a fibre link.

"FX, TX, LBT, LLF are OFF. "

According to this manual:

FX Fiber link
On - The fiber link is ok
Off - No link, or the link is faulty
Blinking - Receiving data on the fiber

TX Ethernet Link
On - The UTP link is ok
Off - No link, or the link is faulty
Blinking - Receiving data on Ethernet

So it looks like you don't have a working fiber or copper connection. The copper is slightly less troubling since it is likely due to the 10/100 switches not working on gigabit connection. The first issue to correct is the lack of a FX light.

Have you swapped the TX and RX fibers at one end to see if the FX light will come on? If so then it is time to proceed to fixing the copper problem. If not you will might need to get the fiber techs back in to fix the problem.

Remember the fiber on the TX port on one converter goes to the RX port on the other converter.

TX ------- RX
RX ------- TX

I find it very strange that the shop that sold you these converters is all of a sudden recommending a $250 media converter and a $75 SFP module. I don't think your switches can use SFP modules. It is VERY possible they don't know what they are talking about.

If it were my decision a lot would hinge on the returnability the two Startech Media converters. These units sell for around $170 each. If the shop will refund your money take it and run. They likely sold you incompatible hardware and/or sold you on something you didn't need but cost over $100 per unit more. I can't tell from here but they may not have your best interest at heart and if you have other choices I'd do some investigation.

Anyway, if you can return the gigabit converters switches then what you want are 2 MCM110SC2 or MCM110ST2 modules depending on connector type. One for each end. You should come out almost $200 ahead.

If you can't return the gigabit converters then an inexpensive option is to get a pair of Dell PowerConnect 3024 switches off eBay. Here is an example eBay Link $80 delivered for the pair.

But FIRST you have to be sure you have a fiber link! If you can't get the FX LEDs to light on the existing media converters then you likely will have problems no matter what parts you use...

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