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Acoustic Echo Echo that is the result of feedback that is generated on any phone or speaker phone or headset from the speaker to the microphone.  (also see Line Echo)

ATA Analog Telephone adapter  A device that coverts analog voice signals to digital signals which can then be transmitted over the Internet. 

Attendant (Auto Attendant)  An automatic response system, such as a voice presenting options such as press 2 for sales, 5 for Lisa, etc., which handles incoming calls and sends them to the appropriate phone or message.

Attenuation (also referred to as loss) is a term that occurs with any type of signal, (digital or analog) and refers to the reduction in the strength of the signal, which is natural consequence of that signal traveling over the specific medium for long distances.

Backbone  A high speed fiber network with a large capacity that connects major cities throughout the world.

Bandwidth    Usually measured in 1000 bits per second (kbps), it is the amount of data that can be carried from one point to another in a given time period.

Baud   One signaling element per second, not to be confused with bits per second.

BOYD Bring Your Own Device  Some VoIP providers allow a person to supply their own equipment or ATA.

CDR Call Record Detail  Details about a specific call that includes duration, origination, destination, and billable information, as well as other pertinent information.

Codec   Normally used to reference to converting analog signals to digital or digital signals to analog.  It can be used in conjunction with compression software to compress and decompress these signals to varying degrees.

CPE  Customer Premises Equipment  Equipment at the customers location that converts the digital signal back to voice.

CSU/DSU Channel Service Unit/Data Service Unit  A hardware device usually associated with a T1 that acts as an interface and converts data frames from a LAN to a WAN topology.

CSR Customer Service Record  A document required for all phone numbers that will show information that is tied to that number including services, billing activity, associated address and service orders.

Data  Usually treated as a synonym for information, but when used as a description for network topology refers to all traffic other than voice.

Data Transfer Rate   The speed of travel of a given amount of data from one place to another.

DHCP Dynamic Host Control Protocol  A communications protocol that lets network administrators supervise and distribute IP addresses from a central point to each computer or device on a network.

DID  Direct Inward Dialing  A service that allows an enterprise to allocate individual phone numbers to each person within its PBX system.

DSL  Digital Subscriber Line  Phone technology that allows a broadband internet digital connection to be carried over existing copper phone lines, while still allowing the phone service carry analog signals over the same line.                                            Top

DTMF  Dual Tone Multi-frequency Also known as Touchtone, it is the signal generated when you press a telephone's touch keys that is sent to the telephone company.  These signals are actually two tones of a specific frequency designed so that a voice cannot duplicate them.  The ability for interactive telephone menus to work correctly across different networks and phone systems is due to the fact that DTMF tones are standardized and are uniquely linked to a number (and # or *) on the telephone keypad.

ECM   Error Correction Mode   Used in conjunction with memory storing fax machines, ECM allows for the receiving fax machine to request retransmission for a page where some errors were detected in the frames of that page.  If the receiving fax machine is unable to receive an error free page the fax transmission may fail and the fax connection terminated.  On networks with some packet loss, fax transmissions will routinely fail when ECM is enabled because of the low tolerance allowed for any packet loss.

IAD  Integrated Access Device  Equipment at the customers location that is used to convert digital signals back to voice.  Usually used in association with a DSL connection. 

IAX  Inter-Asterisk eXchange Protocol, (pronounced "eeks") (now commonly meaning IAX2) is an Asterisk communications protocol for setting up interactive user sessions (both audio and/or video) and supports any type of codec.

IVR  Interactive Voice Response  An integrated software information system that speaks to callers and uses menus and voice responses.  By using touch-tone keypad entries to interact with the software, you get voice responses with real time data.

Jitter   As data load increases and decreases, routers on the Internet can create slightly different times that individual packets take to travel from one point to another point.  This variation in time is known as jitter.

Latency   The time it takes for a packet to reach its destination.  Higher delay times can be an issue, especially for VoIP, where voice delay can be recognized with latency higher than 150 milliseconds.  Higher than 500 milliseconds and the conversation is going to be very problematic.

LERG  Local Exchange Routing Guide  Is a database of the first 6 digits of a telephone number, updated on a regular basis, that provides information for routing telephone calls over the Public Switching Telephone Network, as well as, enables identification of what local company the number belongs to.

Line Echo Echo that is common in the PSTN network and is created as a result of voice traveling over hybrids or 2 wire to 4 wire conversions.

LNP Local Number Portability is the ability of a US telephone customer to retain their phone number if they switch to another local telephone provider.                                            Top

MTA Multimedia Terminal Adapter A device that connects a traditional telephone to a cable line, converting analog voice to digital signals.

NAT Network Address Translation  An Internet standard allowing a local network to use one public IP address to connect to the Internet and a set of local IP addresses to identify each PC or device in the local network. 

PBX  Public Branch Exchange  A private telephone switching system that allows outside phone lines from a telecommunications provider to connect to extensions within the office or building.  They usually have multiple features including call forwarding, rollover, paging and voice mail.

POTS Plain Old Telephone System  The familiar single phone line, single phone number system that has been in existence for many years.

PSTN Public Switched Telephone Service  The combination of local, long-distance and international carriers that make up the worldwide telephone network.

Rate Center The geographic area used by local exchange carriers to set rate boundaries for issuing phone numbers and for billing.

RJ-11  The typical four or 6 wire connector used to connect telephone equipment.                                           Top

RJ-45   An 8 wire connector used to connect Ethernet connections in computers, routers and other Internet devices.  This connector is slightly larger than a (RJ-11) telephone connector.

Router  A router is a device connected to at least two networks that determines the next network point to forward a packet to.  The decision of which way to send each information packet is based on it's current understanding of the networks that it is connected to.

RTP   Real Time Transport Protocol  An Internet protocol that functions for end-to-end network connections for applications that use audio or video.

SIP Session Initiation Protocol  is a signaling protocol for Internet conferencing, telephony, and instant messaging.  It is a request-response protocol, dealing with requests from clients and responses from servers. initiating an interactive user session.

SIP Session Initiation Protocol Trunking is the use of VoIP to facilitate the connection of typically a PBX to the Internet, where the Internet replaces the conventional telephone trunk, allowing a business to communicate with traditional PSTN telephone subscribers worldwide by connecting to an ITSP (Internet Telephony Service Provider).

Soft Phone   IP telephony software that allows end users to send and receive calls over the computer or hand held PC device (PDA) over the Internet.  Typically used in conjunction with a headset and microphone.

STUN  Simple transversal of UDP through NATs  is a protocol for assisting devices behind a NAT firewall or router with their packet routing.

Switch  A switch is a device that keeps a record of the MAC addresses of all devices connected to it and then channels incoming data from any of multiple input ports to the specific output port that will take the data toward its intended destination.                        Top

T38   A recognized standard for sending fax transmissions over an IP network in real time mode.  Messages are sent as UDP or TCP/IP packets.

UDP User Datagram Protocol is a communications protocol that does not provide sequencing of the packets.  The application must be able to make sure that the entire message has arrived and is in the right order.

VAD Voice Activation Detection is a software application, also known as silence suppression that allows the detection of the absence of audio for a specified amount of time to use techniques to conserve bandwidth, as many conversations can actually include one half silence. Voice activation detection can also be used to forward idle noise or comfort noise to a remote IP telephone or IAD giving the illusion of a constant transmission stream during silence, so the listener would not think the line had gone dead.

VoIP   Voice over Internet Protocol   The transmission of voice over the Internet as digital packets rather than the traditional circuit-committed protocols of the PSTN.  VoIP uses real-time protocol (RTP) to help ensure that the packets get delivered in a timely way. 

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