Ricoh M052 Service Manual page 438

680
D BICU serial communication error: Time out
-001
-002 D BICU serial communication error: Retry error
-003 D BICU serial communication error: Download error
-004 D BICU serial communication error: UART error
The serial communication error occurs in the BICU.
Noise
Defective BICU
Replace the BICU.
681 D RFID: Communication error
Communication error occurs when the RFID board starts to communicate
with the ID chip.
Retry of RFID communication fails three times after the machine has
detected the RFID communication error.
Defective RFID board
Disconnected ASAP I/F
No memory chip on the AIO
Noise
683 C RFID: Unit check error
The machine gets RFID communication error even the AIO has not been
installed in the machine.
External noise
SM 6-15
Service Call Conditions
M052/M053/M054