T23G call without registration

[nellog]

Hi, I've a T26P and i can make call without sip registration (ex: from phone to fxo gateway, without pbx). With T23G i get error "Unknown URI Scheme", there is setting for avoid this?
Thanks.

[Karl_Yealink]

Do you mean that you dail the IP of other phones directly?

If yes, please go to web interface->features->generally information->allow IP call, then enable this feature.
If not, please let me know again.