In Ch. 2, it states that it uses Ethernet cable to connect to an "Ethernet hub or switch,' which should be a router. It seems to be similar to the Apex in how the networking is set up, though I don't know it it works with Fusion.
I don't believe the AC3 can use the modern EB8 energy bars and is limited to the DC energy bars. I haven't seen any of them for sale in a long time, which could become a challenge for you. If you've got the AC3, though, it could be worth getting it running and upgrade to a new Apex when funds allow.