Settings of your own phone such as activating the forwarding and answering machine can be easily controlled via the app. Calls can be made from the call list and the contacts or the callback function (called Quickcall) is used to call your own phone first and then the external number.
The prerequisite is a PBX telephone system that is compatible with the solution from www.opennet.ch, www.circls.com or with the OpenSource 2600hz.org, the product kazoo.

This solution is especially suitable for companies that have branches in different locations and want to merge their telephony with each other. The phone number can be easily ported from one location to another and an employee can still be reached with the internal and external number, no matter via the mobile network, the landline phone or a VoiP solution such as MS Teams.
Telephony is provided via the cloud, which can be installed on site on a server in the branches, as well as with a classic cloud operator such as google, etc. Contact me if you are interested in a future-oriented solution.