Why Are There 2 Triangle Light Indicators For Every Port

businessuer

Hi, 
For zyxel switches, why Are There 2 Triangle Light Indicators For Every Port?
I understand that those pointing to the top refers to the interface on top.
I understand that those pointing to the bottom refers to the interface on bottom.
But why 2 triangles for each interface? 

Zyxel_Chris

@businessuer

The green LED means link on 1G and the left one of amber means on 100M, you can refer to our user guide page 43.
XGS4600-32_V4.70_Ed1.pdf (zyxel.com)

Also on front panel sticker has also poin it out. 

Zyxel_Chris

@businessuer
I'm not quite sure what you mean, which model are you use?

businessuer

Zyxel_Chris said:

@businessuer
I'm not quite sure what you mean, which model are you use?

Hi,
In the circled portion, there are 2 triangles up and 2 triangles down.
I notice that when the interface is up, only 1 triangle will light up.
What is the other triangle for?