Codecs supported by a SIP extension can be selected by using the Codecs button. Use Ctrl-Left-Click (holding Ctrl down) to select multiple codecs. Individual codecs can be moved up and down the codec priority list by selecting the codec entry, and selecting the Up or Down buttons. Codecs may specify the integration time in milliseconds after the codec name in the form codec:integrationtime, e.g. ‘g729:40’
When negotiating a SIP call, the codec with the highest priority(at the top of the list) will be attempted first, then the second and so on.