At home, I get my internet service via Comcast, which is a cable TV service provider, though I don't use TV much, but since the local telephone company doesn't provide any sort of high-speed service in this area, well within the city limits of our great city, Comcast is the only option. Their method of providing phone service is via VoIP, though it's disguised as POTS by virtue of their hardware. We get "free" long-distance telecom service within the Continental U.S. bundled with "regular" local service for a monthly fee competitive with the "phone company." The service Comcast provides is comparable in every discernible way with that provided by the local phone company, though neither service is as clean, clear, and reliable as it was before the introduction of cellular service. Cellular service has, I suppose, lowered everyone's expectation of phone service.

These gadgets that masquerade as free long-distance service ports, probably like the "magic jack" attempt to use your internet service to provide long-distance telecom. Some work well, some not so much. I'd guess that what Radio Shack sells is of the lowest available quality and at the highest available price.

RE