FTTH signal attenuation

[Alireza]

so i FINALLY applied for an FTTH internet and my isp just installed the little cabinet port in my house for my router (which i will get tomorrow)

my question is

when they prepare the cable

they told me my signal attenuation is 15.5 db and it is amazing

now i tried to google what it means and it showed me some crazy logarithm which i didn't understand a damn thing since i finished high school a long time ago

but what does it mean?

i got a green connecter with a device which i should connect a patch cord to it

here is a picture

is it a good thing?

what does 15 db means?

is it good?

[PyCCo_TyPuCTo]

Yes, it's perfectly fine.

It means that the difference between Transmit light level and Receive light level on the other side of the fiber is 15.5dB.

For example if at the ISP office they Tx light at +5dBm, then your Rx level at that box is -10dBm. That's all it is. It means nothing in terms of speeds or latency you can get out of that connection. 

 

[Alex Atkin UK]

10 hours ago, Alireza said:

what does 15 db means?

is it good?

As someone said above, its about light loss.  For a passive optical network, 15dB of light loss is about the minimum you will get due to splitter loss and distance.

https://community.fs.com/blog/test-optical-splitters-loss-with-optical-power-meter-light-source.html

Look specifically at the 1:32 value as this is usually how FTTH/P is split.

[Alireza]

10 hours ago, PyCCo_TyPuCTo said:

Yes, it's perfectly fine.

It means that the difference between Transmit light level and Receive light level on the other side of the fiber is 15.5dB.

For example if at the ISP office they Tx light at +5dBm, then your Rx level at that box is -10dBm. That's all it is. It means nothing in terms of speeds or latency you can get out of that connection. 

 

 

2 hours ago, Alex Atkin UK said:

As someone said above, its about light loss.  For a passive optical network, 15dB of light loss is about the minimum you will get due to splitter loss and distance.

https://community.fs.com/blog/test-optical-splitters-loss-with-optical-power-meter-light-source.html

Look specifically at the 1:32 value as this is usually how FTTH/P is split.

thank you so much for your answer