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Old November 2nd, 2017, 06:18 PM   #1
harryting
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Settle a fiber/copper converter question for me.

So our com tech is telling me that one can't use a fiber/copper media converter on one side and another brand's switch on the other side of fiber. He is saying it has to be identical model or else it doesn't work.

Well, I thought something like 1000base-sx is a standard, like 10/100BaseT or 10Base2 for copper. As long it's the same mode of fiber it should work, right? Or am I totally wet?
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Old November 2nd, 2017, 08:35 PM   #2
mk42
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My guess is that it's about "eh, it should work, probably?" vs tested compatibility.

I don't really understand why, but everything I've heard about fiber says that the standards exist, but the vendor implementations somehow don't always quite work with each other anyways.
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Old November 3rd, 2017, 03:49 AM   #3
rdrast
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Your "Com Tech" is a grade A idiot. As long as the fiber mode (single, multi) and speed are alike, any manufacturers devices will work. That's the nice thing about actual standards.
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Old November 3rd, 2017, 04:27 AM   #4
rkicklighter
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I've been in a situation like this, installed by "others" where it did not work. Both converters were multi-mode, both were 1000-FX to Gigabit Copper but they would not communicate with each other.

The issue, one converter used 1350nm light and the other 850nm light. All parameter have to match including the light wavelength. If they do, it should work.
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Old November 3rd, 2017, 04:37 AM   #5
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So here's the thing, you could both be correct.

I've run into *media converters* that use their own proprietary signaling on the fiber side. Those particular units are in fact designed to work in pairs, so you have something like this;

[1000Base-Tx] [Media Converter] <Proprietary signaling over fiber> [Media Converter] [1000Base-Tx]

If you put a switch with a 1000Base-SX\LX SFP on the other side, it won't work.

Now, if you have a 1000Base-SX\LX capable switch (or switch with SFP port more than likely) and a 1000Base-SX\LX capable media converter then yes, you can run fiber between any make switch and any make media converter without issue. (Assuming obvious things like both ends being LX or SX, multimode vs single mode, etc).

At an old facility I had a Ubquiti switch with a Dell SFP SX module, multi mode to the other building which had a Netgear switch with a Cisco SFP SX module. Thank god for standards!

Have your tech read up on the 802.3z standard. That covers pretty much all Gig over fiber.
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Old November 3rd, 2017, 04:41 AM   #6
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As others highlighted... your comm tech isn't the most inquisitive person in the world (which I've seen plenty myself) and assumes that a single failed experience due to many possible reasons is then true for the most obvious reason (different brand).

I sincerely hope he never has to deal with Siemens OLM's for Profibus or he's going to have an existential crisis as they have two models that despite being made for the same thing don't work together and are made by the same manufacturer.
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Old November 3rd, 2017, 04:42 AM   #7
Brandon_K
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Quote:
Originally Posted by rkicklighter View Post
I've been in a situation like this, installed by "others" where it did not work. Both converters were multi-mode, both were 1000-FX to Gigabit Copper but they would not communicate with each other.

The issue, one converter used 1350nm light and the other 850nm light. All parameter have to match including the light wavelength. If they do, it should work.
You weren't using the same standards. Right off the bat, 1000Base-FX doesn't exist. 100Base-FX does however.

If you were in the gigabit over fiber world, your 1350nm side was 1000Base-LX or 1000Base-LX10. The 850nm side was 1000Base-SX.

SX is more common, but LX can be pushed MUCH further distances, at least over single mode.
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Old November 3rd, 2017, 07:07 AM   #8
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Agreed Brandon, it was early, I got LX and FX mixed up. Bottom line is I didn't spec or install the converters but when it didn't work the customer blamed our PLCs and I had to go fix the mess.
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Old November 3rd, 2017, 09:04 AM   #9
James Mcquade
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We always use pairs on all our converters.
we always have issues if their not.

james
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Old November 3rd, 2017, 06:27 PM   #10
Maxkling
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As stated already, it will work, we have done it many times with good results. Sometimes you can't avoid it, sometimes it's a gotta make it work in a pinch. Either way if you match them, they will work.
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Old November 5th, 2017, 11:41 AM   #11
shawn_75
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Perhaps he's not a grade a idiot and is just providing an answer that he is sure will work and won't provide problems for him in the future. After all, the OP DID appear to ask the com guy for guidance.
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Old November 5th, 2017, 06:19 PM   #12
Brandon_K
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Something else to add, if he's the tech, why do you care what hardware gets used? Would you allow him to tell you what PLC to use for a project?
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Old November 6th, 2017, 04:19 AM   #13
tragically1969
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Quote:
Originally Posted by James Mcquade View Post
We always use pairs on all our converters.
we always have issues if their not.

james
Same here, we use the Moxa ones, can't think of a reason why you wouldn't use a pair really, if you do you know they will work, its not like they cost $1000s ?
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Old November 6th, 2017, 10:21 AM   #14
harryting
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Thanks all!

I work in an old world industry where seniority > knowledge. Our com-tech is not the same as our control-tech where they actually have to pass a test but I rather not get into how difficult it is to change union rules.

Also, I think in the early days they might be right since standard weren't as well defined.

There is very good reason I don't want them to do it certain way because it would involve running the fiber to another building 500 yd away then route it BACK to where I want it. By doing it my way they just need to buy a SFP for a spare slot in a switch. Anyhow..
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Old November 6th, 2017, 10:31 AM   #15
Steve Bailey
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Another consideration if you decide to mix different manufacturers, you had better be pretty knowledgeable about troubleshooting them. I expect that if you have problems, when you call tech support, manufacturer A will blame everything on manufacturer B and vice versa.
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