As we saw earlier Expect.pm with some low level networking protocol can be used to access any device that can be connected via some cable.
Or without a cable.
But you might not want to implement the whole protocol, or you might not have a command line tool that can access the device remotely. Or you don't want to use it as you'd like to test that separately.
You can use the built-in telnet/ssh/ftp/tftp clinets in your Unix/Linux machine.