IBM 5281/5282/5285/5286 Data Station Typewriter Keyboard
528X-83 type Model B, aka "beamfoot"
IBM-made 83-key [data] typewriter keyboard for IBM 5281 Data Station, 5282 Dual Data Station, 5285 Programmable Data Station and 5286 Dual Programmable Data Station. It has a 32Ω, 0.2W speaker inside.