Panasonic KX-TDA30 Features Manual page 110

1.7 Busy Line/Busy Party Features
• If none of these notification receiving methods (Call Waiting tone, OHCA, or Whisper OHCA) are set at
the called party's extension, the caller will hear a reorder tone.
Feature Guide References
1.1.3.3 Call Waiting
User Manual References
1.2.4 When the Dialled Line is Busy or There is No Answer
1.7.3 Receiving Call Waiting (Call Waiting/Off-hook Call Announcement [OHCA]/Whisper OHCA)
110 Feature Guide