Just when I think I’m getting a grip on serial communications, some new puzzle shows up. Here’s what I’m thinking about today: I’m considering adding a Fathom-S setup to my BR2 which already has a Fathom-X setup. Why, you ask? I’d like to have the analog camera on board as a backup/rear-view//low-light option, and I also need RS485 communications. Before I thought of the analog camera idea, I was just planning to use one of the three spare wire pairs in the tether for the RS485, but when I looked at the Fathom-S specs it appears that it can do RS422, which is pretty similar to 485, so maybe it might be an easy solution for both. Looking in more detail at the S boards, it appears that they provide 5V TTL serial, which is a different animal than the RS standards. Here are the issues as I see them:
Is there a better way to get the analog camera’s signal up the tether that doesn’t involve the Fathom-S boards? Like maybe I could do that with a single pair, RS485 over another single pair, and still have myself a spare pair versus using three pairs to do it the Fathom-S way?
Can I in fact do RS485 with a Fathom-S setup, and if so, what would that wiring look like? TTL-to-485 converters at both ends?