Panasonic KX-T336 System Reference Manual page 268

3. Automatic Redirection If No Answer
If an incoming outside call (a call routed via a CO line which belongs to a
Trunk Group whose Incoming Mode (Day) is "ATT") ringing on a LOOP
key of ATT1 or 2 is not answered within a specified time (Attendant
Overflow Time), it may be redirected to the extension assigned as the
overflow destination.
Refer to Section 6-G-7.00 "Automatic Redirection If No Answer" for
further information.
KX-T336 System
Overflow Extension
3-D-2-2
(30393)
ATT 1
Ringing at ATT2
ATT 2
↓
No Answer
↓
Time Out (Attendant Overflow Time)
↓
Ringing at Overflow Extension