- 1km of fiber optic cable - https://www.amazon.com/Jeirdus-Launch-Singlemode-Measuring-O... - 1Gb modem - https://www.amazon.com/TP-Link-Ethernet-Converter-Multi-Mode... The price for two modems and the cable is just under $120
Back to your point, fiber came to my mind as well. Why bother running CAT5/6 when you can just run fiber? Maybe its meant for existing infrastructure? But if that's the case, what was utilizing that infra before? Is it just in cases where you happen to have phone lines running between buildings?