PLANET ICF-1601 - Manual (Page 37)

(3) Please select 『off』to P2P mode, and then please insert the SIP parameters
such as User Name, Account ID, Password, Server Address and Server Port.
By the way, the setting is same on the ICF-1601(2).
" Note
After register success, you can see the Register Status from
VoIP LED on ICF-1601
4. To see the register status on IPX-1900.
After both of devices have registered to IP PBX successfully, it could browse to
“Information -> PBX Extension Status” page to show the registration
status:
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