Nestorovic Labs MCC network ???

This weekend found a Nestorovic Labs MCC network (HI Z) that is supposed to be a MC eq. box. Have a switch with 3 positions: min-max-mid . I would like to have some information of this unit, I do not have the manual and there is no information in the web. As per the bluebook here was bild in 1990 and in that time cost was $550,-. Thanks in avdance