if you are running cable tv along with networking
1 - splitter1 to modem
1 - splitter1 to splitter2
1 - splitter2 to adapter1 (Ethernet to modem/router)
1 - splitter2 to existing coax
1 - existing coax to adapter2 (Ethernet to computer)
1 - adapter2 to set top box/tv
So - I would guess at least 6