Checking the status of the POWER4845 on the UA5000 is always a fault. What is the possible reason for this? (Multiple Choice)

Checking the status of the POWER4845 on the UA5000 is always a fault. What is the possible reason for this? (Multiple Choice)
A . The monitor line sequence is incorrect or damaged.
B . The serial port where the monitoring cable is plugged in is incorrect.
C . The hardware of the monitor board of the POWER4845 is damaged.
D . The communication protocol needs to be converted.

Answer: ABCD