There are no circumstances where you will not have use of your phone system, if you are using Solgari.
If you have multiple locations using the Solgari platform, and your data connection goes down in one location, all calls can be routed to any of your other locations. Even if you only have one location you can have all calls routed to cell phones or anywhere you want. Remember your telephony solution is in the cloud so you can choose where your calls go.
For outbound calls the same applies; you can use your smartphone to use Solgari through the mobile application and you can move your extensions to another office.
There are multiple solutions that companies can choose in advance as a disaster recovery position.