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TERMS |
DEFINITIONS |
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2B+D |
The Basic Rate Interface (BRI) in ISDN. A single ISDN circuit is divided into
two 64 kbps digital channels for voice or data and one 16 kbps channel for
low-speed data and signaling. In ISDN, 2B+D is carried on one or two pairs of
wires depending on the interface), the same wire pairs that today bring a single
voice circuit into your home or office. |
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Analog |
Electrical circuit represented by means of continuous, variable physical
quantities (such as voltages and frequencies), as opposed to discrete
representations (like the 0/1, off/on representation of digital circuits). |
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Annotation |
Marking such as that done by highlighting, underlining, text, or freehand
drawing. |
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Application Sharing |
Feature of many document-conferencing packages that lets a pair of users on
different systems simultaneously use an application that resides on only one of
the machines. |
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AT&T 5ESS |
Digital central office switching system made by AT. |
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B Channel |
ISDN communication channel that carries voice, circuit, or packet conversations.
The B-channel is the fundamental component of ISDN interfaces. It carries 64,000
bits per seconds in either direction. |
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BRI (Basic Rate Interface) |
The most common kind of ISDN interface available in the US. BRI contains two B
channels, each with 64 kbps capacity, and a single D channel (16 kbps) which is
used for signaling and call progress messages. |
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CO (Central Office) |
Facility that serves local telephone subscribers. In the CO, subscribers' lines
are joined to switching equipment that allows them to connect to each other for
both local and long-distance calls. |
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D-Channel |
ISDN communication channel used for sending information between the ISDN
equipment and the ISDN central office switch. The D-channel can also carry
"user" packet data at rates up to 9.6 Kilobits. |
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DMS |
Name of digital central office switches from Northern Telecom. Model numbers
start with BCS. |
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Digital |
Use of a binary code to represent information, such as 0/1, or on/off. |
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EWSD |
Name of digital central office switches from Siemens Stromberg-Carlson. Model
numbers start with APS. |
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File Transfer |
Ability to send files electronically to remote participant's. |
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Foreign Exchange |
If your local central office is not scheduled to have ISDN soon, it may be
possible to obtain ISDN service from a nearby central office. This is called
Foreign Exchange. There are additional charges associated with this type of
service. |
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Frame Rate |
Number of images per second displayed in a video stream. Approximately 24 frames
per second (fps) is considered full-motion video. |
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Full-Duplex Audio |
Audio that allows remote sites to speak simultaneously without losing audio
contact (two-way simultaneous audio). |
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Intel Blue |
Specifications required to provision the ISDN line to meet the needs of Intel's
ISDN-based products. This is the only information you need to give to the phone
company when they ask how the line needs to be provisioned. |
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ISDN (Integrated Services Digital Network) |
Completely digital telephone/telecommunications network which carries voice,
data, and video over existing telephone network infrastructure. It is designed
to provide a single interface for hooking up a phone, fax machine, PC, etc. See
Also: How to Order ISDN |
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IXC (Inter Exchange Carrier) |
Generic name for long-distance carriers, such as MCI, AT, or Sprint. |
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Jack Type |
Different types of jacks (RJ11, RJ45, or RJ48) can be used for an ISDN line. The
RJ11 is the most common in the world and is most often used for analog phones,
modems, and fax machines. RJ48 and RJ45 are essentially the same, as they both
have the same 8-pin configuration. An RJ11 jack can fit into an RJ45/RJ48
connector, however, an RJ45/RJ48 jack cannot fit into an RJ11 connector. |
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Loop Qualification
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Test done by the phone company to make sure the customer is within the maximum
distance of 18,000 feet from the central office that services that customer. |
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LATA (Local Access and Transport Area) |
Geographic territory used primarily by local telephone companies to determine
charges for intrastate calls. As a result of the Bell divestiture, switched
calls that both begin and end at points within the LATA (intraLATA) are
generally the sole responsibility of the local telephone company, while calls
that cross outside the LATA (interLATA) are passed on to an Inter eXchange
Carrier (IXC). |
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LEC (Local Exchange Carrier) |
Local phone companies - either a Regional Bell Operating Company (RBOC) or an
independent phone company (such as GTE) - that provide local transmission
services. |
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MCU (Multipoint Control Unit) |
Device that links three or more point-to-point videoconferencing systems into a
multipoint conference, similar to an analog teleconferencing bridge. |
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Mid Span Repeater |
Device that amplifies the signal coming or going to the central office. This
device is necessary for ISDN service if you are more than 18,000 feet from the
central office. |
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NI1 (National ISDN 1) |
Specification for a "standard" ISDN phone line. The goal is for National ISDN 1
to become a set of standards which every manufacturer can conform to. For
example, ISDN phones that conform to the National ISDN 1 standard will work,
regardless of the central office the customer is connected to. Note: Future
standards, denoted as NI2 and NI3, are currently being developed. |
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NT-1 (Network Termination 1) |
Device that is required to connect ISDN terminal equipment to an ISDN line. The
NT-1 connects to the two-wire line (twisted pair copper wiring) that your
telephone company has assigned for your ISDN service. Your ISDN service will not
work if the NT-1's plug is not connected to a working electrical outlet. |
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PBX (Private Branch Exchange) |
Small version of the phone company's larger central switching office. A PBX is a
private telephone switch. It is connected to groups of lines from one or more
central offices and to all of the telephones at the location served by the PBX. |
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Point of Demarcation |
Physical point at which the phone company's responsibility for the wiring of the
phone line ends. |
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POP (Point Of Presence) |
Long-distance carrier's office in your local community. A POP is the place where
your long-distance carrier, or IXC, terminates your long-distance lines just
before those lines are connected to your local phone company's lines or to your
own direct hookup. Each IXC can have multiple POPs within one LATA. All
long-distance phone connections go through the POPs. |
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POTS (Plain Old Telephone Service) |
Basic telephone service - standard single-line telephones, telephone lines, and
access to the public switched network. There are no added features, such as call
waiting or call forwarding, with POTS. |
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PRI (Primary Rate Interface) |
Network cable that carries 23 usable phone lines that run at 64 kbps or 56 kbps. |
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QCIF (Quarter Common Intermediate Format) |
176-by-144 video format defined by the ITU's H.261 specification. Allows signals
to be delivered at 9.115 Mbits/sec at 30 frames/sec. |
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RBOC (Regional Bell Operating Company) |
Seven regional telephone companies were created by the AT divestiture: Nynex,
Bell Atlantic, Bell South, Southwestern Bell, US West, Pacific Telesis, and
Ameritech. |
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SON (Service Order Number) |
Number issued by the local exchange carrier to confirm the order for the ISDN
service. It provides a matching number for cross referencing the order to the
phone company. |
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SPID (Service Profile Identifier) |
The ISDN switch needs to have a unique identification number for each ISDN set
to which it sends calls and signals. See Also: ISDN Troubleshooting Tips "SPID
Format Issues" and Known SPID Formats S/T-interface: A 4-wire ISDN circuit. The
S/T interface is the part of an ISDN line that connects to the terminal
equipment. |
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SVN (Subscriber Verification Number) |
Number issued by the long-distance carrier to confirm the order for long
distance service. |
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Switched 56 Service |
Type of dial-up digital phone service that provides 56 Kbps bandwidth. Similar
to ISDN, switched 56 traffic can travel over the same physical infrastructure
that supports ISDN. Switched 56, however, is an older technology with decreasing
significance. |
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Video Capture |
Process of converting analog video to digital video. |
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Voice-Activated Switching |
Used in multipoint video conferencing so all sites automatically see the video
of the person speaking. |
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Whiteboard |
Document-conferencing function that lets multiple users simultaneously view and
annotate a document with pens, highlighters, and drawing tools. More advanced
whiteboard programs handle multi-page documents and provide tools for delivering
them as presentations. |
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