An intermediary (either hardware or software) is needed to translate back and forth between an analog stream (i.e. your voice) and the digital packets which are transmitted over a network. Recent advances allow for VoIP to connect directly to the basic PSTN telephone system so that internet calls can be made to any phone number in the world.

Another way to place a VoIP phone call is using a microphone and headset plugged into your computer. The number is placed using the keyboard or an internet IP phone and is routed through your computer and on to your cable modem.

A home router to share your broadband connection (such as Netgear, Linksys, or D-Link, etc). A home router is a device that allows you to share your Internet connection with multiple computers or devices. Many of these home routers cost as little as $30.00 to $50.00 and allow you to have a home network in minutes.

To place a call into the regular (PSTN) phone network you will need a VoIP service provider. The Analog Telephone Adaptor (ATA) which will be provided by the VoIP company. The ATA device, shipped to you once you sign up for service, turns your Internet connection into a phone network. If you are using this device with a home router, you just plug it into the network and turn it on to get started.

Or you can hook up an inexpensive microphone to your computer and send your voice through your computer and its high-speed Internet connection.

Also note that your VoIP service provider may permit you to select an area code different from the area in which you live. This means you may not incur long-distance charges if you call a number in your area code regardless of geography. It also means people who call you may incur long-distance charges depending on their area code and service.

Some VoIP service providers offer their basis service for nothing, normally they are providers who provide computer to computer calls.

• Long distance is part of a flat rate service or a fraction of what you would pay a regular PSTN provider. Therefore if you make expensive long distance phone calls and want to minimize costs this is an excellent solution.
• If you have a broadband Internet connection, you need not maintain and pay the additional cost for a traditional phone line just to make telephone calls.
• With many VoIP plans you can talk for as long as you want with any person in the world (the requirement is that the other person has a Internet connection).
• Ability to take your number anywhere in the world.
• Other features like conference calling, choice of any area code, voice mail, call forwarding, caller ID, call waiting, call detail records, voice mail to email, etc. Most of these features are just not possible with a traditional phone.

• The main drawback is the need for a reliable broadband connection.
• Since VoIP requires a live Internet connection, losing electricity means losing your phone service. If you are concerned about losing power, you could install a UPS for your cable/DSL modem and your ATA. Even a small UPS would keep those devices powered for several hours. Alternatively, you could keep a single phone line with no premium services as a lifeline for those times that you might lose your power or Internet connection.
• Emergency 911 calls are another challenge for VoIP telephony, because it's difficult to determine the exact location of a IP address with geographic certainty. Without knowing the exact location, it's also difficult to determine which call center should receive a VoIP-originated 911 call (though most VoIP providers do have 911 call routing based on the address you used when you registered).
• VoIP providers may or may not offer directory assistance/white page listings.
• The voice quality of your VoIP call is also another consideration. Since the data travels across the Internet, there is the potential for dropouts or "burbles" similar to what you might experience on a cell phone. What significantly improves this is well managed IP networks, used by most of the VoIP service providers, coupled with quality of service (QOS) mechanisms built into their ATAs, and a high-quality compression algorithm yields call quality that greatly exceeds that of cell phones and approaches or matches that of traditional phones. Keep in mind that the call quality for VoIP providers who do not manage their IP networks and depend on the Internet for routing will yield varying and sometimes disappointing voice quality and unreliable connections.

There are mainly two kinds of VoIP service providers. Those that offer phone based services such as Vonage, Sun Rocket etc and those that offer computer to computer based services such as Skype, Net2Phone, etc. Each phone based provider has different phone plans suited to different requirements.