Complex sentence: The preferred way to do that is via a Web interface but users can also choose to enter commands in a console that can be reached both through telnet and with a CLI cable who other end is attached to the computer's COM port.
Split into simpler sentences: The preferred way to do that is via a Web interface. Users can, however, also choose to enter commands in a text-based console that can be reached both through telnet and with a special CLI cable whose other end is attached to the computer's COM port.