imagine computers calling each others within a private network but that network doesn't need to be local and also phones can call them via landline or mobile data but also locally and they don't have to be phones, they can also be computers and they not only can recieve call but also make outbound calls to the landline and mobile data but also locally via ip and theoretically that could also work remotely but not only it also does that to phones which are not part of the private network they are in another arbitrary network but you can still call them so its kinda like email but instead of having text you're having voice and there's also jittering because phone used to make bzzz a lot but since we digital now and not analog anymore the bzz is gone but legacy stuff used the bzz as a sync or sth? and people also really like the bzz so that gets emulated by software now? idk setting up telephone for computer is weird