Panasonic KX-TD500 System Reference Manual page 1445

3.24 OGM CPU runaway (DISA)
Error Code
Possible cause of
the malfunction
Countermeasures
Note
50 xx
xx= 01 to 40 : Slot number
1) Runaway of the OGM (CPU) of the DISA card
Is it possible to play the OGM through
the telephone of the operator 1 ?
No
After entering OUS command,
enter the card test command from
the maintenance terminal
Pass
Enter the card INS command
from the maintenance terminal
None
Replace the DISA card
End
15-E-27
Yes
Fault