A topic (that is currently pinned) exists with a tutorial for connecting your Macintosh to the internet using USB -> serial, but it is very outdated and I ran into several issues while following it. I'm going to add further instruction to it (which is mostly copied from a reply to a thread I made).   For starters, some amazon links!   USB->Serial: https://www.amazon.com/gp/product/B00J4N9T9C/ RS422->RS232: https://www.amazon.com/gp/product/B000068OEQ/   O