Panasonic KX-TDA15 - Manual (Page 119)

1.7 Setting the Telephone According to Your Needs
User Manual 119
1.7.9 Protecting Your Line against Notification Tones (Data Line
Security)
You can protect the line against audible notification tones, such as a call waiting tone during a conversation.
Set this feature if your extension has a data communication device, such as a computer or fax machine
connected to ensure secure data transmission.
To set/cancel
Off-hook. On-hook. Enter 1 to set
or 0 to cancel.
PT/SLT/PS
Set
Cancel
1
0
OR
Enter 730 .
3 0 7
C.Tone