Voice-over-IP (VoIP) Explained

A simple explanation of VoIP: using a data network (such as your office computer network (LAN) or the Internet) to transmit voice signals.

Voice-over-IP (VoIP) systems uses an office's data networks (the over-sized phone jack you where your computers plugs into for Internet) to connect the phone server and phones.

When you pickup the handset and make a call your voice is broken into "packets" of information and transmitted over the data network to the phone server.  From there the server either routes the call to another phone extension (an internal office call) using the office network (LAN), routes the call to a remote phone using the Internet connection, or to an outside phone line via one of three line types.

An outside phone line can be one of three types:

1. Analog phone line - sometimes referred to as a CO line, or POTS line, for every phone line you need to use you will need to have a pair of copper wires setup by the phone company.  When using multiple analog lines for a business a feature called "roll-over" is commonly used to utilize one phone number for multiple lines.
2. T1 digital lines - this is a digital feed from the phone company that provide up-to 24 phone lines and can also provide your Internet connection.  T1 lines have many options, including which provider to use, how many lines, and if it should be used as an Internet connection.  The biggest advantage of a T1 line is the service level agreement (SLA): this is a contract that guarantees uptime and service response times in-case a problem should occur.
3. VoIP Internet lines - this type of phone line uses an existing Internet connection to connect to an telephony Internet service provider to make and receive phone calls.  The number and quality of calls are dependent on the type of Internet connection, the telephony provider, and your network equipment and how well it's configured.  Some providers sell special Internet connection with "Quality of Service" (QoS) that guarantees that phone calls get priority over all other Internet traffic.