Voip 101

Voip, short for Voice over Internet Protocol, is the digital transmission of data packets of audio information from a physical or software phone, through the internet, to another physical or software phone. Unlike traditional analog phone service, which converts audio into electrical signals that are transmitted over a fixed path of copper wires, Voip utilizes the connectivity of the internet to transmit audio. Utilizing broadband internet speeds Voip is just as fast and clear as traditional phone service, but is generally much less expensive.

There are two classes of Voip in the industry; residential and business. Residential Voip utilizes the same technology as business voip, but is a means of conveying voice only, and does not include the feature set of business voip service. Business Voip service also includes PBX service, or Private Branch Exchange, which allows a single telephone number to have multiple extensions for the different departments and people within a company.

Traditionally a PBX system used physical extensions that were hardwired to a phone. An IP PBX utilizes IP addresses to route a phone call, allowing more flexibility than a traditional PBX.

PBX systems are available as inhouse hardware, or as a remote hosted service. Hosted PBX has seen the largest growth in recent years as an affordable option over traditional phone service for many businesses.

VoIP phones, or IP phones, are available in 3 different ways. Soft phones, or software phones, are programs that emulate the number pad of a telephone on your computer screen, allowing you to make phone calls using a microphone and speaker connected to your computer. Physical phones, or IP phones, are virtually identical to traditional telephones in appearance, but have an ethernet connection to transmit voice data, rather than a traditional phone jack. Finally, a USB Voip jack allows you to connect a traditional analog telephone to your computer via usb port, and then make Voip calls through the internet.

Typically Softphones and USB Voip Jacks are adequate for residential use, whereas IP phones are preferred for business situations. The cost of Softphones is free in most cases, but the functionality is severely limited. USB voip jacks require both the physical device as well as subscription service, at rates that are targeted for residential use. IP phones require a service provider, and include the ability to use either an in-house or hosted PBX, for the benefit of businesses that require extensions, voicemail functionality, and other business class features.

Glossary

Here are some of the most common terms that you may hear or see associated with VoIP technology. This is not a comprehensive list, and will grow over time, but it should be enough to get you started and cover most VoIP related issues.

• Jitter – Jitter is the time variation of a characteristic of a periodic signal in electronics and telecommunications, a sinusoidal wave, in effect. The Jitter period is the interval between two subsequent times of maximum effect (or minimum effect) of a signal that varies regularly with time.

• Packet Loss – Packet loss occurs when one (or more) packets of data traveling across the internet are lost; failing to reach their destination.

• SIP – Session Initiation Protocol - A protocol that provides telephony services similar to H.323, but is less complex and uses less resources.

• H.323 - An International Telecommunication Union standard for real-time interactive voice and videoconferencing over LANs and the Internet.

• ATA – Analog Telephone Adapter – This adapter is used to convert your analog telephone signal into a digital signal that can then be sent and received via the internet.

• Upload vs. Download Speed – Upload speed is a measure of the ability to maintain web pages on the internet while Download speed is a measure of how quickly one can view web pages. These speeds are almost always different, which is understandable because viewing a webpage requires a lot less bandwidth as compared to maintaining/hosting one.

• PoE – Power over Ethernet – This is a capability of many newer phones which enables them to get their power directly from the Ethernet connection; no electrical outlet required.

• PBX – Private Branch Exhange - An in-house telephone switching system that interconnects telephone extensions to each other as well as to the outside telephone network. Now there are many services that host the PBX; further reducing your costs.

• DID - The ability to make a telephone call directly into another internal extension without having to route through the operator.

• Trunk - A communications channel between two points, typically referring to large-bandwidth telephone channels between switching centers that handle many simultaneous voice and data signals.

• Full Duplex - In telephony and data communications, full duplex means the ability for both ends of a communication to simultaneously send and receive information without degrading the quality of the content.

• Half Duplex – Where only one party can talk and one party listen at the same time.

• Codec - An algorithm of compression/decompressions that is used for IP telephony and other forms of streaming media.

• Bandwidth (bits per second) - It indicates the number of bits that can be transferred to or from a communications device in one second.

• Packet - The unit of data that is routed between an origin and a destination on the Internet or any other packet-switched network.

• Softphone - A software program that runs on your computer that allows you to make and receive calls over the Internet.

• VoIP – Voice over Internet Protocol – A set of protocols that are used to manage the transmission of phone calls over the Internet.

• Protocol - A formalized set of rules that computers use to communicate.

• Latency – A measure of how long it will take for a packet of information to travel from one point to another.

• PSTN – Publicly Switched Telephone Network - The world’s collection of interconnected voice-oriented public telephone networks.

• Router – The device that connects a number of networks together and transmits packets of data between them.

• Gateway - A device that acts as an interface between any numbers of networks to connect dissimilar communications systems.

• Internet Protocol – IP – The protocol by which data is sent from one computer to another over the Internet.

• LAN – Local Area Network – A network of computers and other associated hardware that share a common communications line and are located within a small geographic area.

• WAN – Wide Area Network - A communications network serving geographically separate areas.