Certified Communications

Dallas, Texas  USA

TELEPHONY GLOSSARY

10Base-T

Also known at Twisted Pair Ethernet.  See Ethernet.

100Base-T

A newer version of Ethernet that operates at ten times the speed of a 10Base-T Ethernet.  See also Ethernet

Application

A software program.

Bandwidth

Amount of data that can be transmitted in a fixed amount of time.

Bridge

A device that connects two LANs or two segments of the same LAN.

Browser

Software used to display sites on the World Wide Web.

Call Park

A call park number allows the user to “park” a call at a specified directory number, go to another phone and dial the “park” number to retrieve the call.  This is different from Hold because the user can retrieve the call from any phone on the same system.  The system administrator must configure a call park number or range for this feature to work.

Circuit-switched gateways

The process of configuring and maintaining an open circuit between two or more gateways so those gateways have the exclusive use of circuit until the connection is released.

Client

An application on a computer that works in conjunction with a server to perform some operation.  An IP Phone is an example of a client.

Client/server

The process of workload sharing between the client, the server, and the network.

CO  (Central Office)

The place the local telephone company uses to do the required processing and to physically switch calls to other exchanges or carriers required for completion; frequently used as a synonym for LEC (local exchange carrier).

CSU (Channel Status Unit)

A device used in conjunction with a T-1 multiplexor that monitors each channel of the T-1 to ensure it is functioning properly.

Database
A collection of information organized so that a computer application can quickly select pieces of information from it.

D-Channel
An ISDN channel used to carry control signals and customer call data in a packet switched mode.  Provides the signaling information for each of the voice channels (known as B-channels).

DHCP
DHCP Service is a client/server system available with Windows NT Server.  DHCP automatically assigns IP addresses to devices whenever you plug them in .  For example, this allows you to connect phones anywhere on the IP network and DHCP automatically assigns IP addresses to them.  You can also move phones from one location on the network to another with no configuration.

Directory number
The telephone number or internal extension assigned to an IP Phone.  For example, 1001.  The directory number is assigned to the phone itself, not a location or a user, so if the phone is moved, it still retains the same directory number.

DTMF (dual tone multi-frequency)

System used by touch-tone telephones where specific frequencies or tones are assigned to each key so it can be easily identified by a microprocessor.

EEPROM
A special type of PROM (programmable read only memory) that can be erased by exposing it to an electrical charge.

Ethernet
A LAN protocol used for connecting computers, workstations, terminals, printers and other devices located in the same building.  Also known a 10Base-T, which signifies the Ethernet data transfer rate of 10Mbps.

Flash memory
A special kind of EEPROM that can be erased and reprogrammed in blocks instead of one byte at a time.  Flash memory resides in a chip when the power is turned off.

G.711
An audio compression standard used for digital telephones on a digital PBX/ISDN.  G.711 uses a bandwidth of 64 Kbps.  G.711-compliant devices can communicate with other G.711 devices, but not with G.723 devices.

G.723
An audio compression standard used for digital telephones on a digital PBX/ISDN that produces digital audio at either 6.4 or 5.3 Kbps.  G.723-compliant devices can communicate with other  G.723 devices, but not with G.711 devices.

Gateway
A device that links two different types of networks.

H.323
A communications standard that allows dissimilar communication devices to communicate with each other using a standardized communications protocol.

Hub
A common connection point for devices in a network.

IP Telephony Solutions
A software and hardware product suite offering an IP alternative to traditional Private Branch Exchanges (PBXs).  Includes IP phones and server software enabling voice and data over an existing LAN and WAN infrastructure.

ISDN (Integrated Services Digital Network)

Network that carries digital voice, video, and data over regular telephone lines.  See also PSTN

ISP (Internet Service Provider)

A company that provides access to the World Wide Web.

IVR (Interactive voice response)

A device using remote touch-tone telephones with a digitized, synthesized voice that reads information on a computer screen to the distant caller.

Kbps (Kilobits per second)

Measure of data transfer speed.

LAN (local area network)

Linked computers that are geographically close together, for example, in the same building. See also WANs.

LEC (Local Exchange Carrier)

See CO

MBps (Megabytes per second)

Measure of data transfer speed

Microsoft NetMeeting
A virtual meeting application from Microsoft. NetMeeting allows you to share applications, a virtual whiteboard, transfer files, and chat with other NetMeeting users

Modem (modulator-demodulator)

A device or software application enabling a computer to transmit data over a telephone line.  A modem converts digital data to analog or transmission, and vice versa.

MTP (Media termination point)
A media termination point is a virtual device that allows transfer, forward, conference and hold features on any G.711 u-law call between an IP Phone and any H.323 gateway, gatekeeper, or client.  A call using MTP automatically converts A-law to u-law (and vice versa), if required.

Multicast
A process of transmitting messages from one source to may destinations.

NANP (North American Numbering Plan)

Any number that can be connected in North America.  For example 214-555-1234.

NetMeeting
See Microsoft NetMeeting

Network
A group of two or more computer systems that are linked.  Examples include LANs and WANs.

Nodes
Computers on networks.

Off-hook
A change in line voltage caused when the receiver or handset is lifted from the hookswitch.  A traditional PBX or local telephone company recognizes this line voltage change as a request for dial tone.

On-hook
A line voltage condition caused when the receiver or handset is resting on the hookswitch.  A traditional PBX or local telephone company recognizes this condition as an idle state.

PBX (Private Branch Exchange)

A small to medium sized customer premise telephone system that is also a switch (computer) providing communications between onsite telephones and a exterior communications networks.  PBX systems are connected to the CO with trunks.  On a PBX, an outside line is normally accessed by dialing “9”.

POTS  (Plain Old Telephone Service)

Standard telephone service used by most residential locations.

PRI (Primary Rate Interface)

A type ISDN service designed for large organizations.  Includes many B-channels (bearer channels) and one D-channel (data channel).

Protocol
Defines a common set of rules and signals that computers on the network use to communicate.  Ethernet is an example of a LAN protocol.

PSTN (Public Switched Telephone Network)

Better known as your local telephone company.  The PSTN network carries voice data over analog telephone lines.  See also ISDN.

Repeater
A network device used to regenerate or replicate a signal.  Used by transmission systems to regenerate analog or digital signals that were distorted by transmission loss.

Route group
A route group allows you to designate the order in which analog access ports and digital access gateways are used.  All members of a route group must have the same route pattern.  Route groups are optional.  For example, if you  use two long distance carriers, you could set up a route group so that long distance calls to the less expensive carrier are given priority.

Route point
A route point lets you designate the order in which route groups are used.  If you are adding route groups, you must add a route point that includes those groups.

Router
Device connecting two LANs.  In addition to providing an interface between two LANs, routers also offer message filtering and network management capabilities.

Routing filter
Allow you to restrict the routing patterns users can dial.  Routing filters can only be used with routing patterns that use the North American Numbering Plan.

Scalable
Refers to a software application’s or a hardware device’s ability to migrate from small operations to large operations with little effort or cost.

Server
A computer or device on a network that works in conjunction with a client to perform some operation.  The Windows 2000 server is an example of a server.

Switch
A network device that filters and forwards a piece of a message (also called packets) between LAN segments.

T-1 (or T-1.5)

A digital device that combines the output of up to 24 regular telephone lines for transmission over a digital network.

TAPI (Telephony Application Programming Interface)
TAPI is an application program interface for connecting a PC running Windows to telephone services.

TCP/IP (transmission control protocol/Internet protocol)

A suite of communications protocols developed by the Department of Defense in the 1970’s that connect hosts on the Internet.  The reigning standard for transmitting data over networks.

Telephony
The science of translating sound into electrical signals, transmitting the signals, then converting them back into sound.

Third Party Call Control
Used in TAPI development; if an audio stream terminates at some location or physical device other than your application or device, you have third party call control.

Traffic
The load on a communications device or system.

Trunk
Circuits that connect two telephony switching systems, such as a PBX and a central office.  A trunk is a voice and data path that simultaneously handles multiple voice and data connections between switches.  See also CO.

WAN (wide area network)

Computer network where the computers are not necessarily geographically close and are linked by telephone lines or radio waves.  See also LANs. See also network.