Use an audio cable for Internet connection

I want to use an audio cable to share an Internet connection between 2 computers. Rather than using an Ethernet crossover cable, I would like to use audio cables instead. If the bandwidth is too low, then perhaps use a system with multiple audio inputs/outputs in order to increase bandwidth. I already have a Tor hotspot that I share with Ethernet crossover. But now I want to do the connection with an audio cable instead of Ethernet, for security reasons. There is already a system for sharing data with audio. It is called "Minimodem" Here is some information on Minimodem: [login to view URL] " Minimodem is a command-line program which decodes (or generates) audio modem tones at any specified baud rate, using various framing protocols. It acts a general-purpose software FSK modem, and includes support for various standard FSK protocols such as Bell103, Bell202, RTTY, TTY/TDD NOAA SAME, and Caller-ID. Minimodem can play and capture audio modem tones in real-time via the system audio device, or in batched mode via audio files. Minimodem can be used to transfer data between nearby computers using an audio cable (or just via sound waves), or between remote computers using radio, telephone, or another audio communications medium. "