MNET Services>Telecom Data Networking>Glossary of Terms and Acronyms

AGCAutomatic Gain Control. A way to normalize the volume level regardless of speaker's position relative to microphone.
ANSAutomatic Noise Suppression. Reduces background noise from audio signal.
AnalogAnalog refers to information represented by a continuously varying value.
Application Contact, VideoA person that is either a room contact or a scheduling contact for video site.
BandwidthA measure of the information-carrying capacity of a communications channel; the speed at which data can be transferred. Normally measured in bits per second or bytes per second.
BaudSymbols per second. If the symbols carry one bit of information each, this value is then also the speed of transmission in bits per second (bps). Informally, this term is often used interchangably with bits per second.
Billing ContactA person that is responsible for the contractual and financial aspects of a site. See also the role information.
BinaryA numbering system having only two digits, typically, 0 and 1.
BondingMethod for making several communication lines look like one, higher-rate line.
bpsBits per second. "kbps" is a unit representing one thousand bits per second. "Mbps" is a unit representing one millsion bits per second. "Gbps" is a unit representing one billion bits per second.
BRIISDN Basic-Rate Interface consisting of 2B+D channels. Nominal speed of the entire line is 144 kbps.
BRI NetworkISDN Interface to a modem or similar device.
BridgeObsolete. An old name for a Multipoint Control Unit (MCU) that can link multiple video conferencing systems for multipoint calls.
Broadband CommunicationsTerm characterizing both digital and analog transmission systems. Broadband communications is generally understood to indicate either a fast data-rate digital system (at least 1 Mbps) or a wide bandwidth analog system. There is no accepted uniform defition of the speed at which a system is considered "broadband."
Call Detail Records(CDR) Records created by the system and the gatekeepers that contain information about calls.
Call RateThe bandwidth used for a voice or video call. The rate includes the audio portion, the video portion (if any), and the control traffic that must be real time. Typical call rates are 80kpbs for a voice call, and 384kbps and 768kbps for video calls.
Camera PresetsPresets are stored camera position settings that can be called up quickly.
CentrexA specific form of classic telephone service offered by MN.IT Services using commercial carrier facilities.
CIFCommon Intermediate Format for video. The image size is 352 x 288 pixels and it is at a rate of 30 frames per second. It is an optional format in the H.261 and H.263 optional standards.
CircuitIn general, the physical connection (or path) of channels, conductors and equipment between two given points through which data may be transferred. More specifically, such a path provided by a service provider.
ClassicMN.IT Services' term for any circuit-based telephone service, as opposed to VoIP. Centrex and ISDN are both considered forms of classic service.
CLI GalleryThe brand name of the equipment used in some of the 225/235MNet interactive video network sites. The gallery houses the main camera, speakers, codec, VCR, and other equipment.
Coaxial CableA type of cable used for broadband data and cable systems where one conductor is completely surrounded by the other. These cables are very resistant to electrical noise. Also know as "coax."
CodecCoder-decoder. A device that converts the analog video and audio signals to digital and compresses them for transmission. It simultaneously decodes incoming signals, converting them back to analog for viewing and listening. Used in the past; the preferred term is now system.
Common CarrierA telecommunications organization that offers communications services to the general public via shared circuits at published tariff rates. In the United States, the Federal Communications Commission and various state public utility commissions regulate common carriers.
Compressed VideoAll video is compressed, in the sense that only a subset of what the camera's lens sees is recorded. When video is carried so that there are no visible picture or motion artifacts, it is referred to as "broadcast" or "full motion" video. As of 2007, compression technology is at a point that 640 x 480, 30 frame/second video (with full audio) can be carried at broadcast quality in about 2Mbps of bandwidth (using the best-avaialble encoders). By 2012, full HD video of 1920 x 1080 x 30 frame/second video (with full audio) can now be carried in that same 2Mbps. Consequently, video transmitted in less bandwidth will show picture or motion artifacts and hence "look compressed."
CompressionThe method of taking raw data and processing it so that it may be represented with less information (or bits in the digital world). Compression falls into two categories: lossless, where the original data may be completely recovered and lossy, where the representation of the original data contains errors. In the latter case, the errors are not necessarily audible or visible to the viewer.
ConferenceSee event.
Conference ChairpersonThe individual at the host site facilitating the meeting.
Continuous PresenceThe ability to see more than one far-end site at a time in a multipoint call.
Control PanelSee Touch Screen Control Panel.
CSNCircuit Switched Network (for example ISDN or POTS).
DatabaseInformation or files stored in a computer for subsequent retrieval and use.
Default GatewayThe address of the interface that is the "next hop" on the way to the Internet. The default gatway is typically on a router or firewall. Typically, a computer is connected to a device called a switch or a hub. Several computers connect to the switch. Devices connected to the same switch do not need a router to find each other. However, if the PC or other device you need to connect to is not local to your switch, the default gateway finds it. If there a valid path, the connection is made. Note that some switches can be divided up into more than one virtual switches to allow grouping of devices like IP phones on some ports and PCs on others. The default gateway for the IP phones would be different from the one the PCs see, so a router would be needed for a PC to find a phone. Even though the IP-phones and PCs are connected to the same physical switch, software can logically keep them separated.
DeviceThe term device or is used to refer to any type of network device (router, switch, etc.). The term network device is used in places where the network context can't be inferred from context; it means the same thing as device.
DigitalRepresenting information as a series of discrete values. Small errors in these values can be corrected by restoring the value to the nearest discrete value. Digital signals can thus carry information more reliably than analog signals.
Direct Broadcast Satellite (DBS)A satellite system designed with sufficient power so that inexpensive earth stations can be used to receive signals.
Document Stand/Graphics CameraThe mounted camera system used to transmit graphics.
DSThe DS series is a hierarchy of standard digital serial communications links. Four speeds are defined: DS-0, DS-1, DS-2, and DS-3. The standard has separate provisions for US and European systems: this glossary will only cover the US systems.
DS-0A DS-0 transmits at 56 000 bit per second. It is the standard version of a "56K" line. It can carry one voice channel at 8000 samples per second of 7 bits each.
DS-1A DS-1 contains 24 DS-0 lines plus additional signalling data. Nominal bandwidth is 1 544 000 bits per second. It is often referred to as a T-1.
DS-2A DS-2 contains 4 DS-1 lines (or 96 DS-0 lines) plus additional signalling data. For all practical purposes, these are not used in the US.
DS-3A DS-3 contains 28 DS-1 lines plus additional signalling data. Nominal bandwidth is 43 232 000 bits per second.
DSCP(also knowns as Differentiated Services Code Point or Diffserv). A method of marking IP packets to indicate the desired quality-of-service level for those packets.
DSLDigital Subscriber Line. A service that enables the use of regular analog telephone lines to carry data. Speeds range from 128 kbps to many megabits. Specific speeds vary depending on line quality and distance.
E-RateFederal government program that makes grants to elementary and secondary schools covering discounts on carrier services, including not only Internet access but also a raft of other offerings.
E.164 identifierITU-T recommendation for international telecommunication numbering, especially ISBN, B-ISDN (Broadband ISDN), and SMDS. E.164 identifiers look similar to telephone numbers and in fact are drawn from the same numbering plan. Sometimes also called "E.164 numbers."
EncoderThe special case of a system where the device a laptop or or desktop computer equipped with special hardware to interface with a camera and microphone(s). A web camera is sufficient, but a true NTSC camera works better. There are also turnkey systems available from a few manufacturers which offer quicker setup and technical support.
End PointObsolete term; the preferred term is now system.
EventA video call with two or more sites participating.
FCIFFull-CIF. Another name for CIF
FECCFar-End Camera Control
Fiber Optic CableA cable containing one or more optical fibers.
FocusA camera control. Focus is used to improve the clarity of the transmitted image.
FrameOne complete video picture. A frame may be comprised of two fields (interlaced video) or may be whole (progressive or non-interlaced video).
Freeze-Frame GraphicsSnapshots with double resolution quality.
Full-Duplex AudioTwo-way audio may be captured and reproduced simultaneously (i.e., you can both listen and speak). With full-duplex audio, the microphone may capture local audio for transmission while the far end audio may be heard clearly. Interruptions and double-talk are possible.
G.711/722/728The industry standards for audio (711 & 722) - and PictureTel's 728 audio enhancements for clarity.
GatekeeperA gatekeeper is a device for binding E.164 addresses to IP addresses and for managing the bandwidth and call control for systems. The gatekeeper page has information on the MN.IT Services gatekeepers. Its functions include: translating E.164 identifiers telephone-like numbers to IP addresses, admission control (controls who can place calls), limiting transmission rates globally or by location, creating call detail records, putting a video call on hold (some cases), transfer of video calls (some cases). MN.IT Services' gatekeepers perform the first four functions above. MN.IT Services uses them mainly for admission control and to allow video users to dial a phone number instead of an IP address.
GatewayA gateway is a device that converts one set of protocols, addresses, or ways of moving data to a different set. Routers used to be called gateways, but they normally don't do conversion and so the term is obsolete when referring to routers. Firewalls or network devices that do NAT can be considered to be gatways. For video, a gateway enables connections between different network or session types. For example, an IP video system connected to the conferencing with an ISDN system connected to the PSTN (Public Switched Telephone Network). MN.IT Services has several gateways in its video network.
Geostationary SatelliteA communications satellite, with a circular orbit 22,400 miles in space. The satellite is stationary in the sky when viewed from earth.
GigEGigabit Ethernet.
GMTGreenwich Mean Time: the baseline for determining the time of day and time zones.
GraphicsCharts, graphs, notes, pictures or flat art that may be transmitted across the network.
Graphics CameraA table-top camera (usually with attached illumination) for showing printed material or three dimensional objects. This camera's output would normally be connected as a live-motion source while in use. The output of this device is standard NTSC (525 Vertical lines of which 486 are visible) video. A PC's output can also be a graphics source at NTSC resolutions but detail can be lost. When a PC is scan-converted to NTSC, use a minimum font size of 18-point or larger.
H.320An ITU-T umbrella specification covering a method to encode and transmit a video signal over telephone circuits (PSTN, ISDN, T-1). H.320 is still heavily used in some parts of the world.
H.323An ITU-T umbrella specification covering a method to encode and transmit a video signal over IP networks. It is part of a family of standards. The standard is at
H.264An ITU-T umbrella specification covering a method to encode and transmit a video signal. It is part of a family of standards. This is the modern video standard used on the web in general; by Apple iPhone, iPad and similar devices; and other tablets and smartphones.
High DefinitionIn theory, better than standard definition. In practice, a marketing term that means very little. For broadcast video, the ATSC defines it to mean a 16:9 image at or greater than 720 lines progressive or 1080 lines interlaced.
Host Site, VideoThe site from which a meeting originates.
Host Site Coordinator, VideoA person who determines the purpose, content, and overall structure of a video conference.
HzHertz, a measure of cycles per second.
IDECIntegrated Dynamic Echo Canceller patented by PictureTel. Dynamically eliminates conference echo so that true full-duplex audio is possible.
Interactive MediaThis term refers to new telecommunications systems designed to permit two-way communications between televisions or computers in one location with software stored on a central computer. Can also allow individuals in distant locations to communicate, teach or learn from one another.
IMUXInverse Multiplexer. Device that bonds two or more BRI lines to form a higher rate channel.
ISDNIntegrated Services Digital Network. A public switched network providing digital connections for the concurrent transmission of voice, video, data, and images. Often seen as a technological bridge between the old, analog telephone system and an upgraded, broadband network. ISDN service can be delivered as PRI (Primary Rate Interface) on a T1 line or as a BRI (Basic Rate Interface) over standard twisted-pair wire phone lines. PRI has 23 usable 64kbps channels and BRI has 2 channels. Both types also have a smaller channel used for call signaling. ISDN PRI can also be referred to as 23B+D (23 channels which are the bearer channels and 1 is the Data [signaling] channel. It enables dial-up H.320 delivery of data and can also carry voice. Videoconference systems can often accommodate 4 to 6 BRI connections for calls up 768kbps (6-lines X 2-channels per/line) * 64kbps/channel. Video bridges, like MN.IT Services', can accommodate 1 or more PRI lines.
kbpsKilobits per second. Unit representing one thousand bits per second. The 'k' should always be lowercase.
LANLocal Area Network. A network that extends over a small area. Typically, the portion of a network that remains within a room, floor, or building is considerd the LAN portion. Contrast with WAN.
MbpsMegabits per second. Unit representing one million bits per second. The 'M' should always be in upper case: usage of 'mbps' would be one thousandth of a bit per second!
MCUMultipoint Control Unit: a device that can link several video conferencing systems into a single conference. The MN.IT Services MCUs can connect IP systems on MNET or anywhere, provided they meet certain criteria and have a routable IP address. MN.IT Services MCUs can also add telephone participants, IP webcams (best effort) and ISDN-connected video systems, as well as Switched 56K connected systems.
ModemModulator-demodulator. Converts digital signals to and from analog.
Multipoint ConferencingMultipoint conferencing occurs when more than two sites are on-line, connected simultaneously. Every site has the ability to view the others, although not simultaneously.
NATNetwork Address Translation. NAT is used where addresses on one side of a network device need to be different on the other side. Sites that use RFC 1918 private addresses often use NAT.
NetworkThe connections over which computers or other devices are connected with one another, such as over a telephone network.
Network AdministratorThe person or organization that provides the communications between MN.IT Services and the person or organization that actually manages a customer data network (except in large organizations, they are often the same people). Duties typically include assigning addresses, configuring equipment, managing cabling, and configuring security policies.
Network DeviceThe term network device or is used to refer to any type of network device (router, switch, etc.). The term device is used in places where the network context can be assumed.
NT1Network termination equipment for ISDN BRI. Turns a U interface into an S/T interface. Not needed when connecting to most digital PBXs.
NTSCNational Television Standards Committee. A standard for broadcast television in US and Japan. Theoretical resolution of 720x480, 30 interlaced frames per second.
Open-NetworkAn industry wide standard that allows different telecommunications vendors to interconnect with a network.
PALPhase Alternating Line. European television format.
PanA camera move. To pan is move the camera side-to-side in a sweeping motion.
Participant Site, VideoThe site(s) from which the meeting does not originate, but contains active participants.
PIPPicture-In-Picture. A second smaller window inside the main screen.
Point-to-Point ConferenceA conference occurring between two points (locations) on the network.
PortThe physical interface between a device and a circuit.
POTSPlain Old Telephone Service.
Power Cam 100High end optics and zoom camera
Power Mic360 degree pick-up microphone for flexibility in meeting attendees' seating placement in room.
PRIISDN Primary Rate Interface. 23x64 kbps (T1 in the US, Japan, and similar countries), 30x64 kbps (E1 in Europe, China, and other countries).
Private AddressesPrivate addresses are a set of addresses that are guaranteed to not be routed across the Internet. They consist of the blocks:
They can be routed within an organization and MN.IT Services uses private addresses extensively. The MNET Private and Non-Routed Address Space Policy document covers their use.
PT724A proprietary audio for PictureTel giving 7khz of audio while only using 24 kbs of the ISDN phone line.
PTZPan-Tilt-Zoom. Camera functionality.
Public Switched Telephone Network(or PSTN) The telephone system.
QCIFQuarter-CIF picture resolution. 176x144 pixels. H.261 and H.263 mandatory format.
QoSQuality-of-Service. Quality-of-service is the ability for a network provider to identify different types of traffic and handle them according to those types. It enables a network provider to ensure that, for example, voice traffic can be delivered with the required inter-packet timings.
RFCRequest For Comments. RFCs are the main Internet design documents. They specify network protocols, document "best practices," and establish standards. They are available from the RFC Eitor at
RFC 1918This is the specific document that governs private addressing. See the private entry.
RoleA role is a way in which a person or organization interacts with MN.IT Services regarding a service. The video section on this site has a clearly laid out set of roles.
Room Contact, VideoA person that is responsible for operational support, and management of a video site. See also the role information.
RouterA router is a network device that performs layer 3 (the IP layer) packet routing. Many devices can perform both routing and switching functions, which is why we use the term network device or simply device.
RSVPThe Resource Reservation Protocol (RSVP) is an IETF standard designed to support resource (for example, bandwidth) reservations through networks of varying topologies and media.
Scheduling Contact, VideoA person that is responsible for scheduling a video site. See also the role information.
Scheduling System, VideoMN.IT Services uses the Tanberg Management System (TMS) for scheduling video conferences. MN.IT Services strongly recommends using TMS for all conferences. Note that conferences scheduled using TMS have priority over ad hoc conferences.
SiteA site is the room that can participare in video conferencing. If the system serving the room is not located in the same room as the participants, the site name - which is also the name assigned to the system - uses the number of the room the participants are in. Contrast with the term system, which refers to the equipment.
SubnetA subnet collection of systems off a particular customer control point interface. All systems in a subnet share the same network block.
SubzoneA subzone is collection of subnets within a zone grouped for bandwidth management purposes.
SwitchA switch is a network device that performs layer 2 (the Ethernet or MAC layer) packet switching. Many devices can perform both routing and switching functions, which is why we use the term network device or simply device.
Switched 56AT & T network providing connections at multiples of 56 kbps.
Switched VideoA residential and business video service in which customers can dial up others (much like today's telephone service) and through which customers can order video-on-demand and other video-based services. Sometimes called video dial tone.
SystemThe unit at the site that encodes and decodes the audio/video signal, as well as performing call control functions. Codec and end point are other, now obsolete, terms with the same meaning: system is the preferred term. Compare with site, which refers to the room the system is in. See also encoder.
T-1A T-1 is the old term for a DS-1 lines. Nominal bandwidth is 1 544 000 bits per second.
T.120Standard for data conferencing and conference control for interactive multimedia communication both multipoint and point-to-point.
Technical ContactA person responsible for the technical implementation and support of a video site. See also the role information.
TeleconferencingThe simultaneous visual and/or sound interconnection that allows individuals in two or more locations to see and talk to one another in a long-distance conference arrangement.
TiltA camera movement. To tilt is to move the camera up and down in an arc without changing the camera's physical height from the floor.
Touch Screen Control PanelThe panel that controls cameras, audio, video switching, source selection and transmission during a meeting.
VCSVideo Conferencing System. Another term for a video system.
Video ConferenceSee event.
Voice-ActivatedIf three or more sites are in a conference call, voice activation causes the conference to show the person who is currently talking.
Voice AdministratorThe person or organization that provides the communications between MN.IT Services and the person or organization that actually manages a customer voice needs (except in large organizations, they are often the same people). Duties typically include telephones moves/adds/changes, arranging for audio conferences, ordering language line services, and similar actions.
VoIPVoice over IP. The provisioning of voice services using packet-based service, specifically TCP/IP.
VPNVirtual Private Newtorks. A VPN is a completely isolated IP network with its own routing table. Routers can carry multiple VPNs and traffic in each VPN is completely isolated from all that in all other VPNs. IP addresses (such as those in the network) can be safely reused from one VPN to another.
WANWide Area Network. A network that extends over a large area. Typically, the portion of a network that connects buildings, crosses public rights-of-way, or involves service providers is the WAN portion. Contrast with LAN.
Wireless Infrared KeypadControl system that enables meeting flexibility by not tethering the control panel to a particular place.
Zone A zone is a collection of sites registered to a single gatekeeper.
ZoomA camera control. It means to change the size of the image optically without actually changing the distance between the subject and the camera.

Network Hub Sites

MN.IT Services' network has three types of sites: customer, aggregation, and hub.

A Customer Site serves customers at one location. It has these characteristics:

EnvironmentNormal office.
PhysicalCustomer provides physical security.
AccessEither business day or 24x7 per customer requirements.
PowerRegular 20A/110V line power. UPS or similar are optional.
TelephoneCJDN sites have MN.IT Services-provided analog phone line. For other sites, a customer-provided analog phone line that accepts incoming calls is desired.
ConnectivityCustomer purchased.

An Aggregation Site serves customers from multiple location. It has these characteristics:

EnvironmentClimate controlled including A/C and humidity control.
PhysicalCustomer provides physical security.
PowerRegular 20A/110V line power. Number of circuits is engineered per site. UPS is required.
TelephoneMN.IT Services-provided analog phone line connected to MN.IT Services device at all times.
ConnectivitySingle, specified by MN.IT Services.

A Hub Site provides area redundancy and serves customers from multiple location. It has these characteristics:

EnvironmentClimate controlled including A/C and humidity control.
PhysicalSite coordinator provides physical security.
PowerRegular 20A/110V line power. Number of circuits and other power requirements are engineered per site. UPS and generator with 72 hour capacity are required.
TelephoneMN.IT Services-provided analog phone line connected to MN.IT Services device at all times.
ConnectivityDual or greater, specified by MN.IT Services.