If you’re looking to use 100BaseBX fiber with the EtherScope nXG or LinkRunner 10G, it’s important to note that these devices do not natively support 100 Mbps fiber connections. However, there is a simple workaround using a compact fiber media converter.
https://www.networxproducts.com/fiber-media-converter-100base-bx-wdm-sc-30km-1310t-1550r
These are incredibly small and would connect to the ethernet port.