Default [Q] automatic sip calls?

Hey there,

Hope some here can give me a hint.
Is there a terminal command for starting a sip call to a specific number?
I know there is one for the standart phone apk but I need my tablet to do the call so it must be a sip call.

I need this for a backup alarm clock. So if a car (with the tablet inside) istīnt leaving the wlan zone, the tablet īs giving me a call.

Thanks so far, if you got some help for me it would save me some needed sleep