So, for example, this cable would work? https://www.ebay.com/itm/2936612111...cxX6sv0C3w%3D%3D|clp:2334524|tkp:BFBM8oDKpstfYou can either use a standard Apple printer-type cable (8-pin male to 8-pin male mini-DIN with RX/TX swapped), which I think some people still make for some reason, or you can get a pair of LocalTalk boxes and a suitable cable, or a pair of PhoneNet boxes and a suitable cable. Anything you can use to connect two Macs over LocalTalk will work with this.
(Note this means that straight wired 8-pin cables won't work, but they won't work to connect two Macs either)
(Sorry, @Scott Squires, didn't mean to repeat you! that'll teach me not to read to the end before clicking 'reply'....)