This will be short: I have a screenshot for pjsua, but I think that might be all I can offer on it.
pjsua is a command-line SIP client — in other words, a software phone.
Personally I put things like this in the same mental box with Skype or Ekiga or linphone. I’m ashamed to say that Skype is the only one of those three I have used beyond a cursory startup, and I quit it not long after the Microsoft takeover. Not that my decision was related, but. …
Anyway, pjsua appears to have plenty of options to run your online phone needs. I have to say “appears” because I don’t have a SIP number that I know of, except perhaps via my GMail account, and I thought that was only available to U.S. residents. Or at least that’s what it told me last time I checked.
I can’t say if this is better than linphone, but suspect pjsua is a little more technical than linphone. Of course, to be honest, I’ve used both linphone and pjsua about the same amount of time, so what do I know … ? 😕
Regardless, I’m betting either one is better than Skype.
So my unfortunate brief encounter with pjsua boils down to, “Looks good, probably sounds good too.” 😐