To connect this analog telephone to an internet router, plug a standard RJ11 telephone cable directly into the port labeled Phone, Tel, or FXS on the back of the router. If your router lacks a built-in phone port, connect an Analog Telephone Adapter (ATA) to an open LAN port on your router using an Ethernet cable, and then plug this phone into the ATA's phone port - I use an ATA adaptor.

From a smoke-free home