Ah! You got me down the right rabbit hole. I think I was actually using INTERSVR and INTERLNK but yes, must have been a LapLink cable.

https://en.wikipedia.org/wiki/List_of_DOS_commands#INTERSVR_...

That was magic for me the first time I transferred a file between computers. I didn't have to re-type my code! What a time to be alive.

Before Arduino and the analog Square reader, the parasitic-powered serial port wireless X-10 Firecracker seemed magic level to me.

https://www.x10.com/products/cm17a

The serial null modem cable with 4 ends commands you!