Step 1 : Select codec 'G729' or 'iLBC' ONLY. Press the menu button beside the "clear"

Step 2 : Select system setting

Step 3 : Select sip proxy

Step 4 : Select default

Step 5 : Enter the data according to the screen

Step 6 : Password = Line password as below.

Back, and all saved.
Then dial the number as the format:
00+ country code + phone number
example 006046158100