With Teams 2 pstn It become very easy to call the public telephone from your laptop as well receive the calls into your portable device. It doesn't matter if laptop, desktop, mobile or table since you got the Teams client  and the correct log-in in to your tenant, as per the usual Office work, you are reachable from the same geographic numbers of your office's PBX. This service overlays the PBX structure and if you wish you can still mantain the old pbx network and phone.  Through the Microsoft Azure and BZS cloud you can work anywhere exactly like you were in your office with your fix telephone included! It is also the easiest way to reach other company users.