VoIPUSA.com - Voice Over Internet Protocol Information and FactsArticles, news, facts and more related to VoIP and Internet Phones
Voice over IP (VoIP) Technology Explained. Page 1
Companies that are serving VoIP are called "providers", and protocols which are used to carry over signals over the IP networks are referred to as Voice over IP or Voice protocols. They may be viewed as commercial realization of the experimental Network Voice Protocol. Sometimes VoIP to VoIP calls are free, while VoIP to PSTN (Public Switched Telephone Network) may have a minimal cost for the user.
Generally there are two kinds of PSTN to VoIP services. One is DID (Direct Inward Dialing) and the other is Access Number. DID is a service of local companies that provide a block of telephone numbers that is calling into a companyís PBX system (Private Bank Exchange). By using the latter a company can offer its customer individual phone number without having a physical line to the PBX for each connection. It has a monthly fee. Access Number requires to put the caller to input the extension number of the user and itís usually free for the user while the caller will have to pay.