Stupid fiber question

[Mucman]

I was helping a friend rewire their colo rack which also had a fiber channel storage array. I've never really deal with fiber but one thing came to mind when I was re running the cables... how do you know which way to plug it in? There were no labels on the fiber or the fiber interface. If I just made a note of how it was in and made sure I plugged it in the same way . Does it actually matter which way I plug it in? Is their some autosensing thing on the interface that will swap the TX and RX interfaces in case it is in backwards?

Like I the title says, it's a stupid fiber question

 

[bozo1]

It does matter but usually, they'll only fit properly in one direction.

 

[Tallgeese]

<< how do you know which way to plug it in? >>

never used it for fibre channel myself, but when using it for Ethernet backbones, I've always just plugged in the jumper. If I didn't get a link light, I simply swapped the two connectors (ST)...BINGO!

<< Is their some autosensing thing on the interface that will swap the TX and RX interfaces in case it is in backwards? >>

Some equipment might, but nothing immediately leaps to mind...

 

[Mucman]

Cool, thanks for the fast response!

 

[ScottMac]

Regardless of which connector type you have, if you look at the cable closely, there's usually writing on only one side/strand. If there's no writing, then there may be a texture on one side.

Many ST or ST-Type connectors have different color strain reliefs: SC connectors are frequently in a clip (side-by-side)already in position. SC connectors will only go into the recepticle in one orientation (unless you force 'em really hard).

Jumpers, with rare exception, are usually marked in some way, just look at the jacketing if there's no tag, marking, or color difference on the connectors proper.

Worse case, as Tallgeese mentioned, plug 'em in, if there's no link light, swap the connectors.


Good Luck

Scott

 

[Tallgeese]

better response from scott...as usual

 

[Garion]

Actually, it's not the SC connector itself that's keyed - It's usually the bracket that's holding the two ends together. I've seen a LOT of SC cables without the bracket. I've always figured that it takes a LOT longer to try to look at the cabling and chase down the send/receive - I just plug 'em in and hope for a green light. Works about 50% of the time!

- G

 

[Tallgeese]

Is there a standard for the position and/or color of the "Send" and "Receive" strands tho?

As in:
SC connector => [ SEND ] | [RECEIVE]

 

[ScottMac]

None that I'm aware of. I believe that transmit tends to be on the right (as you face the device).

Some fiber (especially the ST and ST-Type) are usually red and black, I (for no pa'ticular reason) usually put the red connector in the upstream transmit. The only reason I even started doing that was so if I had a customer on the phone I knew what the cable layout was by (personal) convention.

It also indicated occasionally when someone was screwing with my fiber......

My other (minor?) compulsions are to set the rack screws in alignment (slotted screws with all the slots vertical, phillips with the marker dot at 12:00 o'clock)... maybe some others ...who pays attention? Some stuff ya just do outta habit.

FWIW

Scott

 

[Tallgeese]

<< My other (minor?) compulsions are to set the rack screws in alignment (slotted screws with all the slots vertical, phillips with the marker dot at 12:00 o'clock)... maybe some others ...who pays attention? Some stuff ya just do outta habit. >>

A peek into the tortured mind of a data networking genius...ONLY ON AT!

 

[ScottMac]

I'm not a network genius (!), but I've met a few.....pretty scary folks. Many of the authors / speakers (Radia Perlman, Doug Comer, etc) seem pretty normal though (I'm not talking about them).

Besides, I'll never admit to being anything other than a better-than-average guesser.......


FWIW

Scott

(this post count was "1337") fairly fitting.....

 

[dave5317]

SN=Snap and Connect?

IF the first end is conected to a TX port, the other end has to be connected to the Rx port, and vice versa.

 

[dave5317]

 

[dave5317]

sorry for the dups, was meant to say SC=Snap and Connect

 

[bigshooter]

if it doesn't work with sc (side by side ones right?, it's been a while ) then just pull the ends out of the bracket and switch them. I've had premade cables that come in wrong on one end (well it can't be wrong on both ends, otherwise it would work ) and you jsut switch them around. That's why the new ends are nice (not ST, aren't they the ones you twist on? ) you can't mess them up.

 

[ScottMac]

"can't mess 'em up?" CAN'T ??? Oh man, you must have Nirvana customer/users...

I know people that have had to rush out new blades, because some !!PERSON!! decided that the SC jack "was a little tight" and used PLIARS to help push the connector in (upside-down / sideways), cracking the cuff of the recepticle, and pretty much breaking the transceiver module loose from the PCB (hanging by a couple solder pads).

Remember: "Just when you figure you've got something "Idiot Proof" someone finds (/ makes / devos) a better Idiot."

So far, MTRJs are looking pretty good. They resemble a standard "phone jack" close enough that most folks can figure out how to plug 'em in without creating an RMA. Density is great, termination is slightly more painful than ST or SC connectors. I'm sure somewhere in the future, someone will plug 'em into a standard copper RJ45, then cut the end off to reterminate because they figured the connector was bad when it didn't work.

FWIW

Scott