[Mike Lu] likes to add serial ports to his routers to use for debugging but ... repurposing the four unused wires on one of the RJ45 Ethernet connectors. This would allow him to interface with ...

also known as the RJ45 port, has existed since the late 1980s. These days, most people use their Ethernet port to plug their router into their computer for faster networking speeds. If you're ...

These cables have RJ45 connectors on each end, which are designed to plug into Ethernet ... be the cause. An Ethernet cable plugs into the LAN port of your router or modem/router combo.