If you are using a FritzFon connected to an AVM FritzBox with DECT, you can use this script to let the phone ring programmatically, e.g. for notifications, alarm system, whatever.
Idea is originally from https://www.administrator.de/wissen/informationen-webinterface-fritzbox-shellscript-auslesen-214598.html, but due to some changes of the Web-Interface of FritzBox, I adapted the script in many places.
Password and username have to be configured of course, username only if necessary.
Tested on Fritzbox 7360