Yes, somebody please explain exactly what this device does. And what's the "NEC SAMPLE" HuCard converter-looking-thing.
It was NECs very early project for network playing. Unfortunately it never made it to practise.
As far as i'm aware the project started in 1987 (according to a prototype draft) while the hardware we know has been built around early 1989.
At the back of it you can find a phone jack connector.
Regarding the HuCard i guess it holds the OS for establishing the network service connection. But it's only a guess.