Went against my better judgement...

[Biscuit]

So I usually dont take really stupid risks... but this time i did.

First some history
Im about to move into a house where my office will be on the 3rd floor but obviously the telephone line is near the front door. My first thought was running a CAT6 cable up there, but after looking at the run and how many bends it has to make, whilst at the same time remaining hidden from children and a nibbly puppy, I had a bit of an idea....

"Those two switches I have" (Cisco SG300)... "they have an SFP on the front of them"... "I wonder how much they are..."

Bit of a look about to learn about what kind I would need, Official ones like £50-60
Compatible ones from a reputable seller with good reviews £20-40
then I came across these...
https://www.empowerfiber.com/p/mgblx1_tr2866

I checked out the reviews and they seemed... fake.. tbqh. Everything in my body was telling me DONT DO IT.

But I did it...

£10 for 2 single mode SFP, with free delivery.

Took 10 days to arrive, I gingerly plugged them in and... THEY WORK. I haven't thoroughly tested the speeds with them but they register as 1Gbps modules

They probably dont have anywhere near the rated output power and the chinese government are probably slurping up all my data, but hell, for ~10% of the price of official ones I'll take a punt at some Chinesium knock offs

[peterb]

I’ve used the ones from fs.com with some success. On the other hand, I bought some fibre test gear from them that was pretty poor and was eventually returned.

But at the price you paid, even if they had been lemons, the outlay wasn’t that much. Good call!

[Biscuit]

I’ve used the ones from fs.com with some success. On the other hand, I bought some fibre test gear from them that was pretty poor and was eventually returned.

But at the price you paid, even if they had been lemons, the outlay wasn’t that much. Good call!

The concern I had was whether or not they would break my switches. They arent exactly mega£$£$£ anyway but would still be ~£100 down the drain.

[Zak33]

are they good then?

how's best to test them?

[peterb]

The concern I had was whether or not they would break my switches. They arent exactly mega£$£$£ anyway but would still be ~£100 down the drain.

The SFP interface is open and so the risk of damage is small.

are they good then?

how's best to test them?

Difficult in a 'domestic' environment. They are 1Gb modules but without access to very expensive test kit, you need multiple sources and multiple destinations and a switch that has some sort of throughput monitoring built in to see what the link throughput is.

Of course, I don't know what Biscuit is sending over it - and there are many reasons where you might use fibre at lower speeds - range, cost, immunity to interference being three common ones. But the speed of any link is determined by the slowest element.

[CAT-THE-FIFTH]

Does it haz lazers??

[peterb]

Does it haz lazers??

They do - the ones biscuit bout are 1310nm devices so they will be laser and the fibre shoul be single mode.

[CAT-THE-FIFTH]

Does it haz lazers??

They do - the ones biscuit bought are 1310nm devices so they will be laser and the fibre shoul be single mode.

I all of a sudden want one.

[peterb]

I all of a sudden want one.

Well, they are cheap enough - but be careful as they are outside the visible range (in the infra-red region)

[CAT-THE-FIFTH]

Well, they are cheap enough - but be careful as they are outside the visible range (in the infra-red region)

So my attack Sharks can attack stealthily and cunningly like a very cunning Fox??!!

[peterb]

So my attack Sharks can attack stealthily and cunningly like a very cunning Fox??!!

[Biscuit]

are they good then?

how's best to test them?

Haven't tested them in detail yet, still putting together my "mini rack".

Note that the switch doesn't actually fit the rack, the way I have mounted it is a proper bodge... But works.




All I will be doing is throwing big files at them and seeing how they hold up. Once I move house and have my office set up perhaps I'll have chance to do a bit more

The SFP interface is open and so the risk of damage is small.



Difficult in a 'domestic' environment. They are 1Gb modules but without access to very expensive test kit, you need multiple sources and multiple destinations and a switch that has some sort of throughput monitoring built in to see what the link throughput is.

Of course, I don't know what Biscuit is sending over it - and there are many reasons where you might use fibre at lower speeds - range, cost, immunity to interference being three common ones. But the speed of any link is determined by the slowest element.

No guarantee that some random Chinese company sticks to the standards and doesn't cut corners though!

Main reason for me is bend radius and thickness of the cable. Much easier for me to route some OS1 than CAT6 up two flights of stairs.

SG300 are pretty feature filled for pro-sumer switches so there is some analysis tools, nothing too advanced though.

[badass]

A very, very important safety announcement. Do NOT look at thee outputs when they are on. Do not look at the ends of the fibre when on.
This is less of a concern with long haul fibre connections because they don't use visible light (but they still do the damage to your eyesight) so there is no temptation to look to see if the fibre is uninterrupted.


Short haul fibre connections use visible (red) light and I have seen engineers doing basic troubleshooting by looking for the red light at the end of the fibre connection.
Don't do it. The laser is concentrated enough to cause damage to your retina. You will not see it after 1-2 incidents but over time your eyesight will be affected!

If you don't want to spend thousands on testing kit (who does) get a cheapo flashing LED tester - much safer.

[Biscuit]

By "short haul" I guess you mean Multi-Mode?

Don't worry about me... Broadcast Engineer... very familiar with Fibre installation.

[peterb]

A very, very important safety announcement. Do NOT look at thee outputs when they are on. Do not look at the ends of the fibre when on.
This is less of a concern with long haul fibre connections because they don't use visible light (but they still do the damage to your eyesight) so there is no temptation to look to see if the fibre is uninterrupted.


Short haul fibre connections use visible (red) light and I have seen engineers doing basic troubleshooting by looking for the red light at the end of the fibre connection.
Don't do it. The laser is concentrated enough to cause damage to your retina. You will not see it after 1-2 incidents but over time your eyesight will be affected!

If you don't want to spend thousands on testing kit (who does) get a cheapo flashing LED tester - much safer.

I’m sorry, but you are wrong on several counts (but entirely correct about not looking into fibre ports).

1. Visible light is only used for very short links, most likely on toslink audio connections and they don’t use a laser led. Visible light injectors are used on communications links for very basic fault finding and fibre tracing - they are not eyesafe)

2. Both single and multimode fibres use infrared which is not visible.

3. ‘Long haul’ (Single Mode) fibre may have more powerful lasers leds so looking into the transmitter is more likely to be hazardous.

4. In Close and Wide Division multiplexed situations, there may be several lasers firing down a fibre, and the powers are additive, so they are particularly hazardous.

In short, (and to repeat what you said earlier)never look into an open fibre port unless you are certain it is dark, either by inspection at the far end, or using a testmeter that covers the relevant fibre spectrum.

[Biscuit]

4. In Close and Wide Division multiplexed situations, there may be several lasers firing down a fibre, and the powers are additive, so they are particularly hazardous.

I presume you mean coarse wave division multiplexing (CWDM) and dense wave division multiplexing (DWDM)?

Not heard it called close and wide before... is this a standard terminology in other industries?