Casio BGP-20 / BGP-200 Manual — Module 931

Two owner's manual PDFs for the Casio module 931, each a different scan (English included). Casio fitted it in the BGP-20 and BGP-200. Casio's spec sheet lists one CR2016U, with 5 years of battery life and accuracy within ±15 seconds a month; the module first shipped in Feb 1991.