On busy
If Call forwarding on busy is configured on the phone, another incoming call during an active call is not signalled. The call is forwarded to the entered call forwarding destination. Even if call waiting (with or without call waiting tone) is configured on the phone, another incoming call during an active call is not signalled.
Configuration
Web interface:
• Telephony > Call forwarding > On busy
For more information, see Call forwarding.Phone:
• Settings > Telephony > Call forwarding > On busy
For more information, see Telephony.Provisioning:
• For more information, see Auerswald DokuWiki