Very similar to what I seek except these appear to be 10G not 1G
I’m pretty certain mine are running at 1Gbps anyway (the switches only support 1Gbps), but I couldn’t tell you whether going for one of their 1 or 10Gbps SFP’s makes a difference.
I doubt it does, although I believe more is done to prevent jitter on the ethernet circuit on the 10Gbps modules. Whether that makes a difference is debatable.
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As Jeremy mentions, some Switch/Router vendors will reject non-appropriately coded SFPs, though most consumer-grade Switches will just ignore the coding.
The coding is carried on EEPROMs within the SFPs, they’re multi-byte fields for things like the vendor name, ID, part #, serial #, SFP version numbers, etc. Depending on the SFP, the coding can actually be reprogrammed “in the field” with specialised EEPROM reprogrammers.
Because large Customers have enough sway to strong-arm Vendors into letting them use (significantly cheaper) 3rd party SFPs, most vendors, including Cisco, have CLI commands that enable the Switch/Router to ignore mis-matching vendor-coded SFP, and just work. The commands do vary depending on the platform/version of Cisco IOS, but the following usually works on Cisco Catalyst Switches;
(config)# no errdisable detect cause gbic-invalid
(config)# service unsupported-transceiver
And just remove/re-insert the SFP 
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Thanks Anup! Good to know, if in the end it is not working after all 
I sincerely hope I won’t need to use such commands to get my now-ordered Trendnet TFC-1000MGAs to work with my also-ordered Finisar modules…
No you don’t - only on the switch there could be a need (when using SFP on the switch)
Torben
Thanks. My switches are RJ45 only so all is good.
FWIW These are the two other modules I found recommended online:
StarTech SFP1000ZXST (I tested with and without attenuators)
Cisco SFP-10G-LR
I tested these alongside the Finisar above and, to my ears, the Finisar sounded better. Others have said it is not possible for the SFP modules to sound different. While I don’t wish to continue that debate, I thought I’d include this information for those who want to experiment themselves.
I will caveat this, however, with the fact that I usually go back and run the listening test a second time many weeks later to see if I still hear a difference. I haven’t had the time to do this so far…
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The first of these would work for my experiment as it’s 1 gigabit (1000Base) and Single Mode. Good to know.
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Why would you use LC/UPC Singlemode Fixed Fiber Optic Attenuator?
Thanks
Torben
In this instance, the StarTech is designed for distances up to 80Km, however I’m running it over just 10m of fibre.
My concern was the power level the receiver was expecting would be somewhat lower than it would be getting and it seemed to make sense to try attenuating the signal (although I believe the StarTech can still handle the levels).
(For LC, I used two attenuators - one for each fibre)
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OK THX :- ) 5 DB? I would be nice if you could share a picture of that 
Are you using Duplex?
Torben
Sure - and, yes, I’m using LC duplex.
As I don’t need to use attenuators in my current configuration, I quickly popped two attenuators on a spare cable. I ordered a range of them, but these are 20dB, which equates to around 50km of OS2 fibre.
The first pic shows the standard fibre connector on its own (to help show the difference with the attenuators on), the second with two attenuators and the third the two attenuators plugged into an SFP.
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@jandersonhill - Great - Thanks. It is nice to learn something new
How do one know (calculate) if it is needed or not?
Torben
PS: Do you use them on the sender side (switch) or receiver side (FMC)?
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In my “travels”, I have encountered a number of modules where the manufacturer talks about using attenuators. Single Mode is generally intended to cover huge distances, as @jandersonhill says, so this sounds reasonable; I’m not sure why some but not all modules need attenuation however.
For example, see https://www.cisco.com/c/en/us/products/collateral/interfaces-modules/gigabit-ethernet-gbic-sfp-modules/datasheet-c78-366584.html
I’m not sure why you use “switch” and “FMC” terminology here, as if people usually use optical cables between a switch and an FMC (whatever this is); do they? I think that for audio purposes, it’s probably more appropriate to speak more broadly of (media) converters. These may or may not be incorporated into switches or whatever, but not always or even usually. I could be wrong; I was once! 
You would need to look at the spec for the SFP to find out its transmit power and maximum receive power. If the latter is lower than the former, given the short distances involved you may run into problems (or, I wonder, even damage the SFP’s).
You could either use an online calculator to calculate the minimum attenuation required, or do as I did and work out something that seems sensible based on the fact normal fibre transceivers cope with up to 10km and extended range up to 80km. 20dB equates to about 50km of OS2 fibre (leaving an effective length of 30km), which seemed reasonable.
I doubt it matters, I’d put them at whichever end makes most sense to you. In my case, hidden!
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Because that is the best way to implement it - switch with SFP (I use Cisco Meraki Go GS110-8-HW-EU switch) to FMC (Fiber Media Converter) and than short ethernet cable to streamer/DAC.
Torben
Ah, so now I know what FMC stands for. Thanks!
It’s one way to implement it 
, though I’m not sure you can claim it’s the best.
Your switch includes an FMC. Everyone who uses SFP or SFP+ modules has to use an FMC at either end, whether standalone or integrated into another device of sorts. And everyone who uses SFP or SFP+ modules should of course ideally be using the shortest possible ethernet cable from the “destination” FMC to streamer.
Perhaps you already know that @jandersonhill uses a switch into a standalone FMC so that’s why you were so specific.
No - I have been using this setup for over a year now.
If you want to use 2 X standalone FMC than you need 2 X GOOD SMPS or LPS and 2 X filter.
But sure you can do that.
Torben
He would only really need a good LPS/Filter at the DAC/Streamer end. The other-end is quite irrelevant when it comes to connectivity over fibre, as electrical noise from PSUs do not not traverse the optical link, likewise for common-mode noise that filters are effective against
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