Brian May via luv-talk <luv-talk@luv.asn.au> wrote:
What software do you use?
I have found recently that csipsimple is not always reliable - especially with outgoing calls. It has a habbit of weird behaviour (e.g. after hanging up sip connection it will immediately make an outgoing mobile connection to the same number), and not always reliable (displays "calling" for outgoing calls with no ringing indication even though the call has actually been answered, leaving the caller wondering what is going on) and sometimes completely crashes during calls. Last update appears to be 2014, in Google Play store.
When I last used an Android device (admittedly three years ago, but we are talking about "old" in this thread), the SIP support was part of the operating system - it was not provided by an app. For reference, the device was a Samsung Galaxy S4, but I suspect the SIP implementation and dialer integration was provided by Google, not Samsung.