GE GFDS250EF Manual page 80

Service Mode Tests
(t5) CRC Non-volatile Memory Test:
The Control shall compute the 16-bit CRC of the non-volatile memory
and compare it with the pre-computed 16-bit CRC that is stored in the
non-volatile memory.
The Control shall sound the Button Press Beep and display "EP" on the
7 segment display after successful 16-bit CRC comparison.
The Control shall display "Er" on the 7-segment display and sound the
Invalid Button Press beep if the 16-bit CRC fails.
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