For the cordless DECT phones you have the option to choose how the target address should be determined.
- from the SIP URL
- from the SIP contact header
To change the setting, Go To: Settings --> Telephony --> Advanced settings --> Determine target address automatically
Example N510 IP PRO: Option manually set to "from the SIP contact header".
Hint: If the transferee and the transfer target are supposed to be in the same local network, addressable via local IP address, the target address will be derived from the SIP contact header.
The option to choose manually is only visible when the parameter is set to "No".