Redefining Unified Communications
VoIP provider serving Massachusetts, Maine, Connecticut, Rhode Island and New Hampshire


Telephony Terminology


Q. What is PDD?
A. Post Dial Delay — is the amount of time that passes between dialing the last digit of a phone number (or pressing Send) and the time the caller begins to hear ringing. During this time the carrier is identifying the possible routes the call can use to reach the destination and one of the biggest considerations that is evaluated is the cost and quality of each possible route (this determination process is often called “Least Cost Routing”). Times longer than 7 seconds are considered a problem by most carriers and should be brought to their attention.


Q. What is VoIP?
A. Voice over Internet Protocol (also called IP Telephony, Internet telephony, and Digital Phone) – is the routing of voice conversations over the Internet or any other IP-based network.

Q. What is SIP?
A. Session Initiation Protocol – is a protocol developed by the IETF MMUSIC Working Group and proposed standard for initiating, modifying, and terminating an interactive user session that involves multimedia elements such as video, voice, instant messaging, online games, and virtual reality.


Q. What is PSTN?
Public Switched Telephone Network – is the concentration of the world’s public circuit-switched telephone networks, in much the same way that the Internet is the concentration of the world’s public IP-based packet-switched networks


Q. What is ISDN?
A. Integrated Services Digital Network – is a type of circuit switched telephone network system, designed to allow digital (as opposed to analog) transmission of voice and data over ordinary telephone copper wires, resulting in better quality and higher speeds, than available with analog systems.


Q. What is PBX?
Private Branch eXchange (also called Private Business eXchange) – is a telephone exchange that is owned by a private business, as opposed to one owned by a common carrier or by a telephone company. Essentially, these are the large dedicated business phone systems in use in many businesses today.


Q. What is IVR?
A. In telephony, Interactive Voice Response – is a computerized system that allows a person, typically a telephone caller, to select an option from a voice menu and otherwise interface with a computer system. The interaction can be touch tone by pressing buttons on the phone or spoken.


Q. What is DID?
Direct Inward Dialing (also called DDI in Europe) is a feature offered by telephone companies for use with their customers’ PBX system, whereby the telephone company (telco) allocates a range of numbers all connected to their customer’s PBX. DIDs are often used to give each extension a phone number that can be dialed from anywhere to reach the extension directly without need for an operator or automated attendant.


Q. What is RFC?
A. Request for Comments (plural Requests for Comments – RFCs) – is one of a series of numbered Internet informational documents and standards very widely followed by both commercial software and freeware in the Internet and Unix communities.