As far as I can tell by looking at eBay and Amazon and aliexpress, I've been completely screwed by the Boomer I bought my KS-RT70 and XL-MK500 from, because he cut the stupid proprietary cable that these units need to connect to each other and I can't find one anywhere. At this point, I'm starting to think that this type of cable doesn't even exist anywhere else but for this one specific JVC head unit produced sometime in the 1980s.
I'm at least glad that the tape deck works, but I don't see a point replacing the failing CD player in my car with a working cassette player and a CD player that I can't even use.
Is it even possible to make this cable myself? Do one of you somehow have one laying around that you could throw up on eBay so I could buy it? Or maybe one of you guys are way better at internet searching than I am and are you able to hunt one down?
Did you know that if you spend enough time on eBay uselessly searching for a specific type of cable that they will start to suspect you're a bot and make you solve captchas? Hahahaha my life sucks...
The closest I have found, is this, this thing appears as if it would allow me to physically plug the head unit into a 13-pin cable that I have already, and plug that keyboard into the CD changer, but there's no possible way the pinout is correct on this, right? https://ebay.us/m/TlR63f