I’m trying to use the arduino board, with ethernet shield to connect to the router via telnet and then run a command in the router and be able to grab the output from the router. I’ve tried a couple methods although I haven’t yet found a direct set of instructions to connect to the router using telnet.
Any help would be great!
There are lots of examples of using http with the arduino. I'm not surprised there are few (if any) telnet examples.
Why not setup a web script on the router which the arduino can call with a GET request and parse the retuned data?
The Telnet protocol is so close to a raw TCP connection that you can probably just connect a TCP socket to port 23 on your target server and read/write ascii character streams. As long as your target server is designed to support a command prompt interface without any data transfer or 8-bit features, it will probably work.
Does your router really use Telnet? That's quite rare these days; SSH is usually preferred.