Panasonic KX-TD500 System Reference Manual page 774

6.00 Cancel Key Function
Description
Allows the attendant to get a line for making a call
on the selected LOOP key again by simply
pressing the CANCEL key.
When CANCEL key is pressed while seizing the
selected LOOP key, dial tone will be heard.
Programming
System Programming
"Group-Trunk Group (1/3)"
Disconnect Time
Conditions
Pressing the CANCEL key does not function
during a conference call and during a
conversation with the SRC side party with holding
the DES side party.
Cancel Key Function does not work while talking
on DES side without holding a call on SRC side.
When a call is made after pressing the CANCEL
key, it is checked against the system toll
restriction procedure, and a call duration time
count is renewed.
Reference
VT Dumb
10-E-1.01 11-C-15.00
6-H-6
Operation
While hearing tone, dialing, or speaking
1. Press the CANCEL key.
CANCEL
• Dial tone sounds.