So, this topic is very similar to this Cisco Switch/Router programming using Arduino?.
I have an Arduino ATmega2560 and Ethernet Shield plus a Cisco 1751 router. I want to configure the router via the console or AUX port using Arduino.
Fast search gave the following results: you could connect to the router using RJ45 to Serial or RJ45 to RJ45 connectors; the protocol is very similar to Telnet (actually works like serial port with text-based commands).
So the main question is – am I able to control the router via a console or AUX port using Ethernet Shield (and an Ethernet library) or do I have to use a serial port connection using something like RS-232?
Update: I’ve noticed one thing – the DB9 port is just an option for easy communicating with a PC so it seems that my idea is not so bad:) See Cabling and Adapter Setups that Work.
As you have pointed out the console and aux ports on Cisco devices are serial ports not network ports so you need to connect to them using RS232, this is an entirely different type of interface from Ethernet.