Need help identifying HP part

Hello, At the Baltimore hamfest last weekend I picked up several 9825 HP-IB interface cables in a box. At the bottom of the box was a Hewlett-Packard IC labeled 1820-0076. It's a 16-pin DIP plastic package with the following stamps: 7476N 7751 SA 1820-0076 The chip looks to be in good shape and is in anti-static foam inside a plastic box. Any ideas what device and purpose this IC might be for? Another mystery device in the box was a 98028A "Resource Management Multiplexer" that has four DB-15 female connectors and what looks to be a 50-pin harmonica-style connector at the end of a short cable. Cheers, Dan PS At the 'fest I also picked up an HP 9915B (with option 002) along with a 98155A keyboard and three interface cables (two serial and one HP-IB) as well as an HP 82905B printer. I also bought three TI-99/4As and two expansion chassis for them (one new in box and the other populated with floppy disk drives and additional memory).