Epson 214D-1 - Manual (Page 13)

Operation 5
HP289
3. Operation
The Model 214D-1 uses a low power CMOS microprocessor to
perform all control functions and calculations.
The instrument is fully configurable with all operating parameters and
calculation constants user settable. (See Section 5 entitled
"Configuration" for information on configuring.) All parameters and
constants are stored in a non-volatile memory which retains data
without battery backup for a minimum of 10 years.
A block diagram of the instrument is shown below.