Terminated: unknown
The grey top part holding the batteries can be replaced by a
rechargeable battery pack called the "CITIZEN RECHARGEABLE
CASSETTE". It takes some practice taking it off (one needs
to press firmly down on the plastic at the front). The
rechargeable battery pack contains two AA sized NiCad cells
which are (with some effort) even replaceable without breaking any plastic
parts.
It is a sibling of the more capable CITIZEN SR II.
It’s very hard to find information on CITIZEN calculators and I have no idea why because this is a very nice and useable scientific calculator. I don’t know if this is an OEM model, I would however be surprised if it is, because of its unique functionality.
The calculator uses a fluorescent display without extra status marks, and uses the decimal dots of the display as status marks. For instance, the third decimal point from the right is used to indicate that the F key was pressed. The leftmost decimal point indicates that non-zero data is stored in memory.
Like any proper scientific calculator, this one can also operate in scientific notation.
The fluorescent display is oriented left-to-right, meaning that when you type a number the first digit shows up on the left side of the display, and following digits are appended at the right.