Parallel interface card (synchronous communication?), evidently for printers, DE9 female.
Miscellaneous Nos. on board: 670-___-____, 820-0027-01
Marked as copyrighted 1979, Apple Computer, Inc.
References: http://mirrors.apple2.org.za/Apple%20II%20Documentation%20Project/Interface%20Cards/Parallel/Apple%20Synch%20Printer%20Interface%20Card%20(Silentype)/