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Configuring your network settings to use Google Public DNS
When you use Google Public DNS, you are changing your DNS “switchboard” operator from your ISP to Google Public DNS.

In most cases, the IP addresses used by your ISP’s domain name servers are automatically set by your ISP via the Dynamic Host Configuration Protocol (DHCP). To use Google Public DNS, you need to explicitly change the DNS settings in your operating system or device to use the Google Public DNS IP addresses. The procedure for changing your DNS settings varies according to operating system and version (Windows, Mac or Linux) or the device (computer, phone, or router). We give general procedures here that might not apply for your OS or device; please consult your vendor documentation for authoritative information. Note: We recommend that only users who are proficient with configuring operating system settings make these changes.

Part One: An Introduction to VoIP
Summary: What Is Voice Over Internet Protocol?
Voice over internet protocol (VoIP) is a communications technology that uses the internet to transfer voice signals in the form of bits and bytes. It delivers these bits and bytes to a specified internet address rather than a telephone number. It’s easier to think of it as being like sending e-mail from one computer to another, but in real time and using voice instead of text. The technology that most likely runs your existing switchboard and phones is a traditional public switched telephone network (PSTN) service. VoIP’s advantage over this is its ability to combine several services, such as voice mail, video, e-mail and conferencing. This instantly increases your ability to collaborate and can result in higher productivity.