Telephone service can be provided by many companies in a variety of different ways. However, there are really only two basic methods, circuit-switched over the Public Switched Telephone Network (PSTN) and packet-switched over the Internet. The PSTN is the traditional network used by the established telephone companies to provide Plain Old Telephone Service (POTS). Some telephone companies use a technology called Voice over Internet Protocol (VOIP) to deliver telephone calls over the Internet.
The PSTN has been around longer and is more reliable but it can be more expensive. VOIP is newer and there can be power, voice quality, and emergency 911 issues. However, with the right provider, VOIP service can be excellent and much less expensive!
Using either technology, calls can be made from one system to the other, as well as from and to landline phones or mobile (cellular) phones.
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| Calls Can Be Made Between All Technologies |
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