DonManfred, Erel, thank you for your answer
in unfiltered LOG I see:
silenseRinger not supported
SecurityException: Neither user 10228 nor current process has android.permission.MODIFY_PHONE_STATE
but I am using (I know that phone SDK is <=23) in Activity_Create this:
rp.PERMISSION_READ_PHONE_STATE
"android.permission.MODIFY_PHONE_STATE"
in code and in Manifest I have it declared too.
I get positive reults of READ phone state
and
negative result ON MODIFY phone state check.
but its Android 5.1, target SDK 27, min SDK=5, I am using SDK = 27
with SDK=15 is everything OK = I can answer the call
Thank you
p4ppc