What's the consensus out there for installing the crossover between two data switches that utilize a fibre tie cable?

I've always seen (and done it this way myself) that the tie cable is NOT crossed over at the patch panels. There would be ONE crossover patch cable in this case.

Recently, someone told me that the standard is to actually cross the pairs inside the patch panel.

Thoughts?

Do the crossover with a jumper.

I make it a point never to mess with any of the structured cabling (copper and fiber). Any special connections, do whatever it takes not to touch behind the jack/bulkhead. This way, the next person should be able to just plug and play.

We always cross the fibers in the tray.

ALWAYS cross over with a jumper(s). Anything else is stupid, heretical, amateurish and........

I'm so mad to read this that I'm sputtering. i've run out of adjectives to describe this lunatic behavior.

Sam

Well Sam, we just do it the way BICSI taught. Since I respect your opinion, I just double-checked the TDMM 11 and it shows the fibers being reversed in the tray. I ordered the TDMM 12 last week and will check once it comes in.

-Larry

Lately, we have been using bi-directional SFP's in alot of our gear. Tx on one wavelength, Rx on another...all on one fiber strand. That way, you do not need to worry about cross-overs and it saves your fiber count.

I'm with Larry on this. We've always put our reverses in the master room. Logic being is the master room controls everything. In the ST days, it didn't matter and everything could be straight and you could just flip the patch cord.

We always "cross" our LC pairs on the cable too. The color code is still intact but on one end the clip is to the left but the other is to the right. This eliminates the customer from keeping track of different polarity of patch cords.

-Todd

I give up. I've obviously either lived too long or have been out of the industry for too long.


Enjoy. Do what you like. Pay no attention to the doddering old man behind the curtain.

Sam

Geeze, how can you argue with BICSI Sam?
-Hal

They USED to be respectable.

Oh, just bring me my gruel and let me sit here drooling in the corner.

"My name is Ozymandias, King of Kings, look upon my works oh ye mighty, and tremble!"


Sam

You can't really blame this on BICSI, they do not make the standards.

I do have an electronic version of the TDMM 12 and it is not as clear as it is in the 11th edition. As far as I can tell, it comes from EIA TSB-125, Guidelines for Maintaining Optical Fiber Polarity Through Reverse-Pair Positioning(2001), which is mentioned in the TDMM 12. I'm guessing because I'm not going to pay to download the TSB-125.

Here is a whitepaper from AMP, or whoever they are now, on the subject.

I don't understand why you'd need a crossover cable when you directly connect two switches side by side but suddenly determine you shouldn't need one when utilizing a tie cable. The one in question was SC duplex by the way.