What is a “line”?

I couldn’t find the explanation of a “Line” in the side panel., is it correct to assume I can dial and send a recorded message to one telephone per line at a time, i.e., if I want to send the same message to 20 different people (telephone numbers) at the same time I would need 20 lines?

Yes. Traditionally, a “line” is a physical telephone line, so to make 20 simultaneous calls, the system needs 20 physical lines. With VOIP service, there is no physical telephone line. A VOIP “line”, also called a “channel” is a virtual line over the internet connection. Conceptually, a VOIP line handles one phone call at a time. To make 20 calls over a VOIP service, you need 20 virtual lines or VOIP channels.

Scalability: the cost per line drops as the the number of lines in a package (Enterprise) increases, as it should and just to make sure, if I upgrade from say 20 lines to 40 lines I pay the difference between the two packages?

The upgrade price is not the same as purchasing together. Please check our online store for upgrade pricing. It is normally much cheaper to purchase a system at once.