Panasonic KX-TVM50 Installation Manual page 185

c)
Set the number of rings before a call is considered "unanswered" and therefore forwarded
to the VPS (Intercept Routing No Answer timer).
1)
Go to the "2-4 System Timer 1/2" screen.
2)
Assign "Intercept Time" parameter.
3)
Click "Apply" to save the changed data.
5.6 KX-TD500 PBX Programming for Inband Integration
Installation Manual 185