Canon VC-C50i/VC-C50iR Programmer's Manual page 171

Answer Format
In case of No Error
d0 d1
Header Device Num
FEh 30h
Data indicates in hexadecimal 2 figures and its ASCII code is Status value.
Example: Data "A"
In case of Error
d0 d1
Header Device Num
FEh 30h
Error Flag indicates in 2 figures hexadecimal and returns ASCII code value.
Example:
In case of Parameter Error :
In case of Mode Error :
Condition of Error flag to be set
Parameter Error •In case of assigned address outside range.
Mode Error •Not in status of Camera ON.
•Not in status of Host Control Mode.
d2 d3
Error Code
3Xh 30h 30h
⇓
⇒
41h
d2 d3
Error Code
3Xh e0
⇓
01010000B ⇒ 50h ⇒ 35h 30h
10010000B ⇒ 90h ⇒ 39h 30h
d4 d5 d6
Status
s0 s1
s0 s1
34h 31h
d4 d5
End mark
e1 EFh
170
d7
End mark
EFh
e0 e1