The reference to ADB in the 4th panel harkens back to 1986, when Apple first introduced their proprietary Apple Desktop Bus peripheral connector. ADB was largely used for keyboards and mice – and had a nice long run on every Mac from the IIfx on up, until it was superceded by USB when the gumdrop iMacs made their debut in 1998.
You can read all about the Apple Desktop Bus. Bonus points if you’re geeky enough to recognize the model number(s) for Bob’s “new” Performa. :)