Terminated: unknown
It has an 8-digit fluorescent display. A blue plastic cover causes the display to be blue, quite like the blue brand markings.
The last operation is repeated when the "="-key is pressed. Maybe hence the "C" in "800C"?
The calculator as a peculiar bug. When negative numbers need all eight digits to display, the minus in front of the number is no longer shown.
Errors are indicated by blinking the display.