Panasonic KX-TD500 System Reference Manual page 1452

3.31 Port link failure (ATT/DPH)
Error Code
Possible cause of
the malfunction
Countermeasures
Note
C yxx
xx= 01 to 40 : Slot number
y= 1 to 4 : Port number
1) Communication disconnection due to unplugged terminal etc.
Check the status of the faulty port
Faulty
Is AC power cord unplugged from
the terminal?
Not unplugged
NG
Set the card with the faulty port to
OUS once, then set to INS and
check the status of the faulty port
Faulty
None
Replace the terminal
Replace the LPR card
End
15-E-34
INS
AC power cord was
unplugged
OK
INS