Panasonic KX-TD500 System Reference Manual page 1475

6.00 Return Messages
=> DN4000
2
***** Executing
3
4
1 COMMON 2
Message
Executing
Illegal Parameter
Invalid status
Illegal level
Display on message line when executing test
← Message line
3 4 5
Description
Executing device test
Entered parameter is out of format or related device is not installed.
The status of the card or port being verified is not "OUS" or "Fault".
The password level is illegal.
6 HRD CPY 7
15-F-15
8