Panasonic KX-TD500 System Reference Manual page 1430

3.09 Check date / time (Real Time Clock IC)
Error Code
Possible cause of
the malfunction
Countermeasures
Note
0700
1) Count up of the Real Time Clock IC is stopped
2) Variances between the CPU clock and the calender clock became greater
than ±30 minutes per 12 hours
Confirm the time displayed on the
PITS/ATT
None
Is the Real Time Clock IC counting
up ?
Set the time from the ATT, PITS,
maintenance terminal etc.
Is the Real Time Clock IC set cor-
rectly and counting up correctly ?
No
Replace the CPU card*
* It is recommended to have a current copy of the program on disk or tape to
facilitate accurate and rapid recovery.
Is the displayed time correct ?
No
15-E-12
Yes
Yes
End