When many people think of VoIP (Voice Over Internet Protocol), they most likely think of cheap or low cost Internet-based telephone services that are a direct replacement for their traditional PSTN (Public Switched Telephone Network) POTS line (Plain Old Telephone Service).
What many people don't realize is that most telecom services are a collection of discrete individual telecom service components "bundled" into a "package" commonly known as.... telephone service, or VoIP service.
These bundled packages will typically include services like "local" outbound and inbound calling privileges. Many jurisdictions require the service provider to include 911/e911 emergency calling (which is not free as some may think). Then for a premium, you can add-on national and/or international calling privileges. Then, one of the biggest hooks is to sell people "unlimited" calling at some other premium package price tag.
Along with all the calling features, they may also offer voicemail, call forwarding, call blocking, auto-attendant, etc, etc, all at incremental premiums that add up quickly, $+$+$+$+$...
Now that we are on the same page of understanding that POTS and VoIP phone services are just a collection of smaller services that are packaged together into a bigger service package, I would like to circle back to the beginning where I started this topic and talk about the very basic essence of VoIP phone service - simple outbound and inbound phone calls.
"Outbound" and "inbound" calling are actually two separate services - typically bundled as if a single service that we think of as "telephone service".