I've had two old Intel PCMCIA RJ45 dongles in my toolbag for 15+ years that I rewired to be inline crossover and rollover adapters. I rewired a couple other'ns I had each with 3 RCA connectors so we could run the A/V to a second TV on the other side of the building at the shop.

I'd'a loved to have that PCMCIA PDA though!