The module consists of a printed circuit board with various components, surrounded by an aluminum frame and Blue plasic 22 pin connector. At the end of the board opposite the connector there is a single micro switch. There is one inspection stamp in the extraction end corner on the component side, and there are several numbered stamps along the sides of the aluminum frame.
Digital Equipment Corporation (DEC)
Printed on the solder side at the insertion end.
Handwritten in blue pencil on the side of the aluminum frame