Internet Telephone VoIP (Voice Over Internet Protocol) – Technology and Terms
If you are just starting to look at VoIP (Voice over Internet Protocol) as an alternative to conventional POTS (plain old telephone service) for your home or office, you will be hit with an all new set of technical terminology and industry jargon. This is a guide to help clarify and define some of the basic vocabulary used in the VoIP world.
Many of these terms are not limited to the VoIP world. As with so many technologies that revolve around broadband access, wireless networking and telephony, you will see these terms elsewhere so it will be helpful for you to understand their meaning as they relate to VoIP.
Telephone Adapter – In the world of VoIP, a telephone adapter is a device that is installed between your network and your telephone hardware. You can think of it as a converter as it sometimes referred to by this term. The most simple of these devices have three connections: power adapter connected to a power outlet, a 4-wire telephone connection where you plug in your conventional telephone hardware and an Ethernet adapter to connect the device to your network. The adapter converts (digitizes) the analog phone signal to an IP protocol.
Codec – Short for coder/decoder, this is a compression and decompression utility that digitizes and compresses the analog voice signal created by your telephone. There are a number of different codecs used and each one offers differing levels of compression. With varying levels of compression come different levels of quality of voice over the line.
VoIP Service Provider – This is a provider of the actual connectivity of your VoIP hardware, your network and the rest of the world. Some provide only computer-based services while others provide complete home or office solutions including multiple phone numbers and fax/data solutions.
RTP – Real-time Transport Protocol is the protocol used to specify standards for carrying voice calls over broadband connections. RTP is used in conjunction with RTCP (Real-time Transport Control Protocol) to provide QoS (Quality of Service) support. This provides a precedence or ‘right-of-way’ traffic control of voice calls over standard traffic over the network. Standard traffic can be thought of as text, email or other low priority, non-time sensitive traffic.
SIP – Session Initiation Protocol controls the way VoIP traffic is transmitted and routed over a broadband network. In simple terms, SIP is the standard by which a session (phone call) is initiated and terminated (phone hangs up).
VoIP phone – This is a telephone that is designed specifically to be used with a VoIP service. It has the functionality of both a telephone in its basic design but incorporates all the functionality of a telephone adapter making is a single, self-contained VoIP device.
Softphone – This is actually a misleading term in that it is not really a phone at all. A softphone is a computer that is equipped with a microphone, a speaker (or headset) and a software program that allows you to make telephone calls without the need for a conventional telephone or adapter.