Parts of IBM terminal controller

Manufacturer IBM

Origin USA
Year of unit Early 1980s
Year of introduction 197?
Type Parts
IBM Manufactured many mainframe computers and terminal systems. The system usually consisted of set of terminals, disk drive and controller unit. Controller unit allowed to connect the system to mainframe using e.g. modem and use mainframe remotely.
These parts are probably from IBM 3274 terminal controller. This controller could drive terminals using special IBM coaxial cable port. But there are few things different than in typical IBM 3274 hardware.
First, the widest board just won't physically fit to slots of IBM 3274. I got all these boards in one package. Because there are no markings I can't figure out what was purpose of this board.
Second is something which looks like CPU on CPU card. It looks very "crude", has some transparent paint on it and has Fairchild marking (with proper, not fake logo), to be exact FC685?? ENG SAMPLE. This is not a typical, mass-manufactured circuit. I can only suspect that it is some kind of testing version.