Casio GS-100 / GS-100D Manual — Module 1549

One owner's manual PDF for the Casio module 1549 in English. Casio fitted it in 4 models, including the GS-100 and GS-100D — the full list is below. Casio's spec sheet lists one CR2016, with 24 months of battery life and accuracy within ±15 seconds a month; the module first shipped in Nov 1998.