This field sets default Phone to phone number. The number which you use add your GSM number at the moment, so VoIPClub robot will call to this number in case of Phone2Phone call.
Choose between Standard and Premium trunks. Premium trunk gives you a better signal and ability to use Caller ID in 95% of countries.
By default VoIPClub application uses port 5060 to connect, but sometimes it's blocked by operator, so you can use port 6000 to call.
This field is about to set the default prefix to all your calls. So you don't need to write it any time you want to call. So if you are calling to same country all the time, set prefix in setting and dial numbers without it.
This option allows you to get dialog pop up when calling through standard Android Phone. So you will be able to choose the way you want to call this person: By using GSM line or using VoIPClub SIP application.
Call logs integration feature allows you to see your regular GSM calls and SIP calls together in one list.