Access network

A term used to refer to that part of the network that connects the exchanges with the customers. Some carriers use the expression “CAN” for customer access network. In the U.S., the access network concept is commonly referred to as the “local loop” or the “subscriber loop”. Depending on the distance to the exchange, the customer density, and other factors, the access network or subscriber loop in some cases is further segmented into two types of plant: feeder and distribution. Many recent innovations relate to access network.

Acousto-Optic

Refers to the interaction of acoustic and optical waves.

Add / drop

Multiplexers used at a network node or point-of-presence to separate out a lower-speed signal from a higher-speed multiplexed signal, or to combine a lower-speed local signal into a higher-speed transport signal.

ADSL

Asymmetric digital subscriber lines. Refers to a technology that uses copper-pair telephone wiring for a high-bit-rate transmission path in the downstream director and a narrow-band path in the upstream direction. The technology has been proposed and evaluated for a number of applications, including switched digital video services, where the application requires enough bandwidth for video in only the downstream direction. The bit rates used in trials for the downstream path are typically 1.544 (T-1) or 2.048 Mbps (E-1), although an extended ADSL technology with 8 Mbps (downstream only) has been developed.

AMPS

Advance Mobile Phone Service

AM-VSB

Amplitude modulated vestigial sideband. Refers to the RF (analog) modulation scheme used with lasers in CATV applications.

ANSI

American National Standards Institute. Refers to a standards-writing organization that organizes committees and overseas the development and publication of standards, including standards for network interfaces, communication protocols, and other communication technologies.

APD

Avalanche photodiode. Refers to a type of semiconductor detector that has an internal gain capability-to multiply the photocurrent resulting from detected photons.

ASE

Amplified spontaneous emission. Refers to a phenomena in the operation of erbium-doped fiber amplifiers that results in higher noise and reduced efficiency.

Asynchronous

A transmission and switching technology that relies on the use of bits or strings of bits at the beginning and the end of the data payload. These are called “framing bits.” This technology differs from synchronous transmission, where the data payload is referenced to a cloak.

ATM

Asynchronous transfer mode. Standard for cell switching to route packets of digital information, designed to accommodate burst data transmission. An ATM cell has a fixed length of 53 bytes: 5-byte header plus 48-byte payload. The standard is a CCITT/ITU and ANSI specification that includes operation at bit rates from 1.544 Mbps up to 2 Gbps. The standard defines both the multiplexing and cell relay protocols.

Bandwidth

In data communications, this refers to the rate of data transmission in terms of the volume of bits per second. The greater the bandwidth of a network transmission protocol, the more data transfer opportunity available in the network.

Baud

A unit for characterizing the signaling rate of a digital link or transmission device. It refers to the number of digital signal transitions in one second. With some data encoding formats, the baud rate is equal to the bits per second. This would be the case with non-return-to-zero formats. In others, such as Manchester, two transitions per bit are required.

BRG

Bragg Reflection Grating

BLSR

Bi-directional line-switched ring. Refers to the use of SONET/SDH multiplexing equipment in ring-configured networks to reroute traffic in the event of a failure with a maximum of bandwidth available between nodes.

Broadband

In contrast with “baseband,” it refers to the ability of a system to transmit or provide for multiple signals simultaneously by modulation of a higher-frequency carrier. The term also is used more generally to refer to the higher-bandwidths associated with video services.

Building Backbone

This refers to a network segment between at least two equipment closets or between a closet and the network interface for the building. According to EIA/TIA 568-A Commercial Building Wiring Standards, the maximum distance for building backbone segments is up to 300 meters. KMI assumes average lengths of 200 meters for each link in building backbone segments in a fiber optic network.

Campus Backbone

This refers to a network region between at least two buildings. According to EIA/TIA 568-A Commercial Building Wiring Standards, the maximum distance for campus backbone segments is up to 2000 meters. KMI assumed average lengths of 500 meters for each link in campus backbone segments in a fiber optic network.

CAP

Competitive access provider. Refers to a company that offers local-access or local telecom services in competition with the local exchange carrier. Example are MFS, Intermedia, and MCI Metro. The CAP industry started in the U.S. during the mid-1980s and has expanded to other markets in the 1990s.

CAT-5

Category 5. High-bandwidth transmission twisted pair copper wire cable.

CATV

Cable television. The initials derive originally from Community Antenna Television. The CATV industry or its networks also are sometimes referred to as “cable,” which can be confusing in discussions of cable markets.

CCITT

Comite Consultatif Internationale de Telegraphique et Telephonique. Refers to the organization responsible for international telecom standards. The CCITT has numerous standards committees that deliberate on, draft, and approve standards on switching, transport, interfaces, cable types, fiber performance, etc.

CDMA

Code Division Multiple Access. A form of digital cellular phone service that features a spread-spectrum technology that assigns a code to all speech bits, sends a scrambled transmission of the encoded speech over the air and reassembles the speech to its original format.

Cellular

Cellular communication transmit voice or data by radio frequencies. A service area is divided into cells – each served by a radio transmitter/receiver. Cells are connected to a mobile telephone switching office, which is connected to the telephone network.

Cellular Network

The cellular system including the mobile telephone switching office (MTSO), radio transmission facilities and cell sites.

Channel

Refers to an electrical or, in the case of fiber optics-based transmission systems, a photonic communications path between two or more points of termination.

CLEC

Competitive local exchange carrier. This term has become commonplace after the 1996 Telecom Act in the U.S. It refers to companies that will offer local telecom services in competition with the previously established local exchange carrier, which would be either a Bell operating company or an independent.

CO

Central office. Refers to a phone company’s switch or exchange location or the building that houses the switch. Also called “serving office” and “exchange.”

Coaxial Cable

Coaxial cable consists of an insulated central wire (“axis”) within a metal cylinder. Used for CATV and has great potential for voice and data.

Core

The term “core” refers to the light carrying portion of the fiber, while the “cladding” is the outer portion of the fiber. In the industry standards for a given fiber type, such as 62.5/125, the 62.5 μm refers to the core diameter and the 125 μm refers to the diameter. Fiber diameter measurements are commonly expressed in microns (μm) or 10-6 meters.

CT

Central tube. Refers to the type of cable that has the fibers housed in a central buffer tube. The fibers can either be bundled together with a binder yarn, or loose within the central tube. The bundled approach usually is used for counts of 12, 18, or more. Most central tube cables usually have two strength members on opposite sides of the central tube.

Dark Fiber

Unused fiber through which no light is transmitted, or installed fiberoptic cable not carrying a signal. The dark fiber is sold without light communications transmission equipment, and the customer is expected to install electronics and signals on the fiber and light it.

Data communications

Digital transmission of information over wired or wireless networks, usually linking computers.

DCS

Digital cross-connect system. Refers to electronic digital cross-connects, which perform signal de-muxing, routing, grooming, and other functions. The DACS (digital access and cross-connect system) from AT&T is an example. Sometimes the terms DCS and DACS are used interchangeably, but DACS is actually AT&T’s product name.

DWDM

Refers to wavelength division multiplexing systems with two or more optical channels in the same transmission window. Systems being deployed in 1999 generally can transmit from 8 channels up to 128 channels in the 12550-nm window, and channel spacing ranges from 1.6 nm (200 GHz) to 0.4 nm (50 GHz). See also WDM.

EDFA

Erbium-doped fiber amplifier. Refers to a product that utilizes a doped fiber as to gain medium with another optical source. The amplification in an EDFA takes place in the 1550-nm “window” of the fiber. Thus the use of EDFAs can have an impact on the type of fiber used in future cable installations. EDFA technology has had an increasing role in U.S. and international markets since 1993.

E-1

The European equivalent of the North American 1.544 Mbps T-1, except that E-1 carries information at the rate of 2.048 Mbps. This is the rate used by European capital CEPT carriers to transmit 30-64 Kbps digital channel for voice or data calls, plus a 64 Kbps channel for signaling, and a 64 Kbps channel for framing (synchronization) and maintenance. CEPT stands for the Conference of European Postal and Telecommunications Administrations.

ELED

Edge-emitting LED. Refers to a semiconductor light source with a structure similar to that of a laser but without the reflective facets to produce a resonator cavity and a single spectral line. ELEDs are contrasted with surface-emitting LEDs, which are commonly used in multimode applications. ELEDs offer better power and beam characteristics than surface emitters, and are used as alternatives to laser diodes in some single-mode applications. See also SOURCE.

ESCON

Enterprise Systems Connection. This refers to a proprietary parallel signal-processing transmission protocol as well as a data network architecture, which were developed and commercialized by IBM in the early 1990s. ESCON is characterized by non-stop high-bandwidth data transfer across distances up to 9 km with multimode technologies, and up to 60-km with single-mode technologies.

Ethernet

This IEEE transmission protocol standard uses Carrier Sense Multiple Access/Collision Detection (CSMA/CD) to transmit data in a network. There are three different network topologies that support Ethernet transmissions: active ring, passive star, and active star.

FCC

Federal Communications Commission. U.S. Agency that implements and oversees telecom regulatory policies.

FDDI

Fiber distributed data interface. Refers to a 100-Mbps LAN standard that was developed specifically for fiber. The standards organization is ANSI. The standard’s specifications at the physical layer include the optoelectronic component footprint and interfaces.

Feeder

The segment of telecom networks that includes equipment, cable, and other hardware for transporting traffic from the switch location into the loop, usually to an outside plant equipment location where there is a passive cross-connect or an active de-multiplex function. Feeder cables can include high-count copper pair cables, where each pair supports one circuit, as well as cables carrying electronically derived circuits. Such electronic feeder technologies include “pair gain” and “digital loop carrier.” “Fiber optic feeder equipment” usually refers to DLC or other access multiplexers.

Fiber Optics

Thin filaments of glass or plastic through which light beams are transmitted over long distances and which can carry enormous amounts of voice and data traffic. Benefits include high capacity, relatively low cost, low power consumption, small space needs, insensitivity to electromagnetic interference (EMI) and improved privacy.

Fiber Channel

An interface standard for serial data transmission developed for communications between workstations and file servers, between computers and storage systems, and between other hosts and peripherals. The standard defines bi-directional point-to-point channels so that the communications path or medium is not shared between multiple nodes. A circuit or packet switching technology can be used to achieve multimode networking. The standard defines a hierarchy of serial data-transfer bit rates and several families of transmission media and sources. The lowest speeds can be implemented on twisted pair, coax, and multimode fiber. The highest speeds can be implemented on multimode and single-mode fiber. The bit rates range from 132 Mbps to 1.06 Gbps.

FITL

Fiber-in-the-loop. Refers usually to local exchange carrier use of fiber in residential or small business distribution applications.

Forward Path

Transmission form the head end toward the subscriber, also known as “downstream.”

FRP

Fiber-reinforced plastic. A material used as an alternative to Kevlar for strength members in some cables, either as central strength members or other strengthening elements. The material is a resin with filaments of fiberglass (not optical fiber). It is also known as glass reinforced plastic (GRP).

FSN

Full-service network. Another term for multimedia or broadband interactive networks. “FSN” was used by Time-Warner (a CATV MSO) for a multimedia service offering that supports voice, video, and data services. Other carriers have adopted the term.

FTTB

Fiber-to-the-business or fiber-to-the-building. Refers to a version of FITL, in which the optical network unit (ONU) is located in a multi-tenant business or residential building.

FTTC

Fiber-to-the-curb. Refers to a FITL architecture with the optical network unit shared among two or more drops, typically up to a maximum of 64 lines. The optical network unit may be located in a curbside pedestal, hand-hole, or enclosure, or it may be in a cabinet in a multi-tenant building.

FTTH

Fiber-to-the-home. Refers to a FITL architecture with one optical network unit for each subscriber.

Gbps

Gigabits per second. Gig is one million.

General Purpose Cable

This type of cable meets specifications for general purpose ratings (UL-1581), and is one of three types of installed in premises networks. Multimode general purpose cables usually have loose-tube construction and are suitable for outdoor installation in campus network segments.

GRP

Glass-reinforced plastic. A strength member material, see FRP.

GSM

Global System for Mobile Communications. The first pan-European digital mobile standard was introduced for commercial use in 1991. It has since been adopted by countries in Asia and Oceania.

Head-end

Facility in a CATV network where the broadcast video signals are transmitted into the feeder and distribution network. Head ends are linked together with super trunks and are linked to satellite downlink facilities with super trunks.

HDSL

High-bit-rate digital subscriber line. Refers to a technology that uses copper wire in the local loop for transmission at rates up to 1.5 Mbps.

HDT

Host distribution terminal. Refers to the equipment in an FITL system that launches the optical signals onto the distribution fibers. The HDT is typically a rack of equipment located in the central office or in a remote terminal. One HDT supports multiple ONUs.

HFC

Hybrid fiber coax. Refers to a FITL architecture with the fiber terminated at a node that serves hundreds of homes. The homes are served from this node by one or more coaxial “bus” cables.

Hub

Refers to the facilities where all customer facilities are terminated for purposes of interconnection to trunks and/or cross-connection to distant ends.

IC

Integrated circuit. Refers to semiconductor electronic devices. This technology has been used to fabricate devices to support a wide number of functions in single-mode transmitters and receivers, including laser drive or modulation, multiplex/de-multiplex, clock recovery and timing, etc.

IEEE

Institute for Electrical and Electronics Engineers. This refers to a standards writing organization that organizes committees and oversees the development and publication of standards, including standards for network interfaces, communications protocols, and other communication technologies.

ILECs

The incumbent local exchange carriers

III-V

“Three-five.” Refers to compound semiconductors fabricated with elements having three and five valence electrons – elements from groups III and V of the periodic table. Examples include the GaAIAs and GaAs material systems used to fabricate lasers in the short-wavelength window of fiber (about 800 nm) and the InGaAsP material system used to fabricate “long-wavelength” semiconductor lasers and detectors for use in the 1300 and 1550 windows of optical fibers.

IM-DD

Intensity modulated direct detection. Refers to a system in which the laser is directly modulated by varying the injection (input) current above threshold and the signal is directly received by a photo detector-based unit. This is the conventional modulation and detection scheme in commercial single-mode systems. Alternatives used in some applications include external modulation of lasers and coherent detection.

Intrastate Access Service

Provides for a two-point communications between a customer’s premises or a collocated interconnection location and an end user’s premises for originating and terminating calls within the same state.

IOF

Interoffice facilities. Refers to cable and equipment installed for transmission between switches in U.S. local exchange carriers’ networks. “IOF” is a Bellcore term and is usually used in reference to the regional Bell companies networks.

ISDN

Integrated services digital network. Refers to a standard for the simultaneous transmission of voice and data, including digital video, over telecom networks. ISDN is a switched service, and the technology was developed to use existing copper-based loop facilities.

ITS

Intelligent transportation system. Formerly referred to as “intelligent vehicle highway systems” (IVHS). ITS is a broad group of systems for monitoring and controlling traffic flow on highways, bridges, tunnels, parking areas, airport access, and others. The technology includes a communications backbone which can utilize fiber optic transmission, as well as remote video cameras, sign controls, and other systems that can be operated remotely from a control center via fiber.

IRU

Indefeasible Right of User. A measure of currency in the under seas cable business. Someone owning an IRU means he has the right to use the cable for the time and bandwidth the IRU applies to. An IRU is to a submarine cable what a lease is to a building.

ITU

International Telecommunications Union. An international organization dating back to 1865 and re-chartered in 1947 as an agency of the UN. It is responsible for international regulations, standards, technical R&D, and various types of planning and support for its members, which include PTTs, government organizations, and other telecom organizations. The ITU publishes various reports summarizing the status of worldwide telecom developments, including documentation of telecom “indicators.”

IXC

Interexchange carrier. Refers to long-distance companies such as AT&T, MCI-WorldCom, and Sprint in the U.S., and refers to facilities-based inter-LATA carriers.

Kbps

Kilobits per second. One thousand bits per second.

LADT

Local Area Data Transport. A method by which customers will send and receive digital data over existing customer loop wiring.

LAN

Local area network. Refers to an on-premises data communication network, usually for linking PCs together or linking PCs to a file server and other data processing equipment.

LATA

An acronym for Local Access and Transport Area established pursuant to the Modification of Final Judgement entered by the United States District Court for the District of Columbia in Civil Action No. 82-0192 for the provision and administration of communications services.

Long-haul Network

Long-distance telecom network or installations. The long-distance application typically uses the highest performance equipment and cable.

LEC

Local exchange carrier. The local phone companies, which can be either a regional Bell Operating Company (RBOC), or an independent (e.g., GTE) which traditionally had the exclusive, franchised right and responsibility to provide local transmission and switching services. With the advent of deregulation and competition, LECs are now known as ILECs (Incumbent Local Exchange Carriers).

LED

Light Emitting Diode. A semiconductor light source without the coherent properties of a laser diode.

L-H

Long-haul. Used to refer to long-distance telecom network carriers or installations. In the U.S., also called interexchange. The long-distance application typically uses the highest performance equipment and cable.

Loop

The connection between a telephone company’s exchange or serving office and the subscriber’s premises. The loop facilities include all cable, structures, and equipment needed to provide this connection. Fiber can be used for part of the loop, such as the link to a remote terminal in fiber optic feeder systems, to a node in HFC systems, or to an ONU in FTTC systems. Fiber also can be used for the entire loop, so that there is no copper transmission path between a CO and the subscriber—a home or business. The expression “fiber-in-the-loop” sometimes is used for just residential or just HFC/FTTC/FTTH architectures.

LT

Loose tube. Refers to cable type with an oversized buffer tube that typically holds up to 12 fibers, with multiple tubes stranded around the center axis. In OSP cables, the buffer tubes usually are stranded around a central strength member.

LSI

Large Scale Integration

MAC

Media Access Control

MAN

Metropolitan Area Network. Refers to networks linking different buildings or locations within the same city. Can refer to a service offering of the local exchange carrier or a CAP, or it can be a private network based on dedicated or leased facilities.

Mbps

Megabits per second. Million bits per second.

Mobile/Wireless Communications

Services that include cellular, wireless data and personal communications services.

MMDS

Multichannel multipoint distribution service. Refers to a microwave technology for delivering television or other entertainment video programming as an alternative to fiber or coaxial based cable systems. In 1995 it was being pursued as an alternative to HFC deployment by some telephone companies seeking a cost-effective technology for competing with cable TV operators.

MOCVD

Metal organic chemical vapor deposition. A semiconductor deposition process used for epitaxial “growing” wafers by depositing layers of compound semiconductor materials, such as the III-V compounded in diode lasers. The epitaxial layers result from a chemical reaction between gas-state compounds of the constituent III and V elements.

MPEG

Moving Pictures Experts Group. Refers to group responsible for standardizing video compression technology under ISO and IEC supervision. Also used to refer to the standard itself, which defines the algorithm used to compress digital video so that less bandwidth is needed to transport full-motion video. MPEG-1 defines a standard for delivering video and audio on a compact disk, which bitrates of 1.2 Mbps for video and 250 kbps for stereo audio. MPEG-2 is for higher-quality images in transmission applications not limited to CD-system bandwidth. MPEG-2 supports interlaced video in systems with bit rates of 3 Mbps or higher. MPEG-1 was published in 1993. The MPEG-2 standard has been adopted and as of November, 1998, MPEG-4 reached the application identification phase of standards review.

MQW

Multi-quantum well. Refers to a semiconductor device technology used to fabricate diode lasers and other optoelectronic active devices. The devices consist of stacked quantum-well layers, which are fabricated by building semiconductor layers with a thickness as little as 1 μm to achieve quantum traps for electrons or holes. Typical devices have active layers and blocking layers stacked up. MQW technology can offer advantages in efficiency and therefore cooling.

MSO

Multiple system operator. Refers to companies that own and operate more than one CATV system. Examples include TCI, Time Warner, Cox, Cablevision, etc.

Multimedia

A system, or a service, or a set of services characterized by two-way communications, interactive services, and the ability to combine data, voice, and video.

Multimode

This refers to the propagation quality of transverse electromagnetic waves in a medium. Inside an optical fiber, multimode refers to the simultaneous transmission of several electromagnetic waves that interact with each other. Emerging from an active device, multimode refers to the multiple wave front spatial quality of the electromagnetic beam.

NEC

National Electrical Code. In the U.S., the National Fire Protection Association has established fire and safety requirements known as the National Electrical Code (NEC). One “article” of the NEC code establishes three levels of safety codes for fiber optic cable as follows:

• OFN – General purpose cables that are satisfactory for use in building wiring but not in plenums or riser shafts. The cables satisfy a test known as UL 1581 Vertical Tray Flame Test.
• OFNR – Riser-rated cables, that are designed to prevent the spread of fire from one floor to another floor in a multi-story building. The cables satisfy a test known as UL 1666.
• OFNP – Plenum-rated cables, that are designed for use in ducts and plenums without the use of conduit. The cables satisfy a test known as UL 910, the “Steiner Tunnel Test,” and are suitable for fire-resistance, low-smoke, and low-toxicity.

Network Access

Linkage to a wired or wireless network.

NGDLC

Next generation digital loop carrier. Refers to DLC systems developed in the late 1980s with the ability to connect directly to a digital switch using high-bandwidth digital interfaces. This eliminates the use of channel banks or terminals for converting from analog to digital in the central office. In the U.S., NGDLC systems comply with key Bellcore specifications (TR-008 or TR-303) for the interface to the switch. Another key feature of NGDLC systems is the use of SONET technology for transporting the multiplexed carriers into the loop, to the remote terminal.

Node

Device in a hybrid fiber-coax (HFC) system which converts optical signals on fiberoptic cable to electrical signals on coaxial cable to the subscribers’ premises. Placed at the end of the fiberoptic cable in a local serving area, typically with 200 to 2,000 homes.

Non-zero DS

Refers to an improved type of dispersion-shifted fiber in which dispersion at 1550 nm is substantially reduced compared with conventional single-mode fiber, but dispersion is not zero at 1550 nm. This fiber was designed to overcome the possible risk of “four-wave mixing,” which is an effect that can degrade transmission quality in WDM systems having multiple channels in the 1550-nm window.

NVOD

Near video-on-demand. Refers to a service offering being developed for providing a menu of video selections without having to switch each channel to each user. One strategy is to start the same program at intervals (say 10 or 15 minutes) on different channels. If a network operator has hundred of channels available, he can offer a menu with many programs. Each program would have enough channels allocated to it so that it can be shown at the various start times.

OC-1

Optical carrier level one. Refers to the basic line-rate in the SONET hierarchy of line rates. All higher-speed rates are integral multiples of OC-1, which is 51.84 Mbps.

OLT

Optical Line Terminal. Terminal equipment residing in a central office or in a remote terminal of a digital loop carrier system located some distance from the central office. It transmits signals to and receives signals from the Optical Network Units (ONUs) in a Fiber-to-the-Curb system. Signals are transmitted in digital format via fiber optic cable connecting the OLT and the ONUs. “OLT” is used in the Full-Service Access Networks Initiative of which NTT is a member. In the U.S., the OLT is known as the “host digital terminal” or “HDT.”

ONU

Optical network unit. Refers to the equipment in an FITL system where the fiber is terminated and the optical signal is converted to an electronic signal. The ONU is located at the home for FTTH and at the curb for FTTC.

OPGW

Optical fiber ground wire. Refers to an aerial cable designed for use on high-voltage transmission towers of electric power companies. Such high-voltage spans operate with a static wire or ground wire to carry lightning or other spikes to ground. OPGW is a fiber-containing alternative to conventional static wire. OPGW adds a communications capability to the grounding function.

Opto-Electronics

The range of materials and devices that generate light, detect light, or control light.

OSP

Outside plant. Refers to all telephone company cable and equipment outside of the central office and operations centers.

OTDR

Optical time domain reflectometer. An instrument for analyzing fiber that can be used to locate faults and to assess splices and connector interfaces. It operates by launching a pulsed laser input into the fiber under test, then detecting and analyzing the return signal that results from reflections and backscattering phenomena.

PBX

Private Branch Exchange. A private phone system owned by a customer, which allows communication within a business and between the business and the outside world.

PCS

Personal communications services. Used commonly to refer to portable/mobile technology based on micro-cell technology. Also called personal communications network. (PCN).

PDFA

Praseodymium-doped fiber amplifier. An optical amplifier based on the use of a fiber-gain medium doped with praseodymium to achieve use gain characteristics in the 1300-nm wavelength region.

PDH

Plesiochronous digital hierarchy. Refers to multiplexed transmission systems that operate without a uniform source of signal timing, as do synchronous systems, such a SONET and SDH. The plesiochronous hierarchy has no detailed line-interface standard, and different hierarchies have been used in different regions and countries. Further, there is no bit rate defined above 140 Mbps in the pelsiochronous hierarchy. For these reasons, SDH (SONET) is considered an improvement, and SDH is replacing PDH for high-bit-rate telecom transport systems throughout the world. The European digital hierarchy is based on the E-1 standard bit rate of 2.048 Mbps. The widely used transmission speeds in this hierarchy 2, 8, 34, and 140 Mpbs.

PHS

Personal Handiphone Service. Refers to a PCS technology developed in Japan and introduced to the Japanese telecom market in 1995.

Pigtail

A length of fiber attached to a device so that it can be spliced into the network. The pigtails on some active devices also may have a connector interface. If one is comparing the cost of pigtailed devices, it is important to check the specifications to see if a connector is included, and if so what the connector specifications are.

PIN

Positive-intrinsic-negative. Refers to a junction diode structure with p-type and n-type doping that is used for a wide family of light-detection devices. Such detectors are often called “PIN diodes.”

Plenum Cable

This type of cable meets specifications for plenum ratings (UL-910 or FT6), and is one of three types installed in premises networks. Multimode plenum cables have tight-buffer construction and are suitable for installation in horizontal and building backbone network segments.

POF

Plastic Optical Fiber.

PON

Passive optical network. Refers to a fiber-in-the-loop system technology that uses passive optical splitters to share the cost of the downstream transmission laser among many subscribers. High split ratios—up to 128:1—have been achieved, and even higher ratios have been researched and demonstrated using EDFAs. The technology includes a time-division-multiple access scheme for combining the upstream transmissions together on the passive optical network.

POP

Point-of-presence. Refers to a facility with equipment for putting communications traffic onto a long-distance network or for taking traffic off the network and routing it to its local destination. POPs can have switches, cross-connects, or add/drop multiplexers. An add/drop is typical for most POPs.

PORT

The access point for competitive carriers to get a connection to the switch and a telephone number. A combination of office equipment and software are used to provide the connection to the network.

POTS

Plain old telephone service.

PSTN

Public switched telephone network.

PTO

Public Telephone Operator. Refers to former PTTs that have been partially or fully privatized; i.e., the national government has divested (sold) part or all of its ownership interest in the PTT to public shareholders, other investors, and/or foreign telecom operators.

PTT

Post, Telephone, and Telegraph. Refers to government-owned or government-run network operators, usually monopoly operators. An example is Deausche Telekom in Germany. A dominant trend that began in the 1980s is the privatization of the PTTs, meaning that the government divests its interest and “sells” ownership to public shareholders or other investors. This is typically accompanied by “liberalization” of the telecom market, meaning that guidelines for competition are established.

RBOC

Regional Bell Operating Company.

Repeater

Refers to a unit of equipment in a fiber optic transmission route for boosting the optical signal so that a longer distance can be spanned.

Resale of Service

The process of purchasing telephone lines and facilities, usually in bulk, and reselling those facilities to individual customers. While some restrictions exist for the resale of residential local service, there are fewer restrictions for business service or long-distance.

Return Path

Transmission from a node in the distribution network toward the head-end. Also known as “upstream.”

RF

Radio frequency. Refers to analog signal processing and transmission technology for applications that include CATV. The term “RF” is sometimes used to refer to electronic or coaxial part of hybrid fiber coax systems in CATV and other broadband applications.

Riser cable

Cable designed for use in elevator shafts, utilities columns, or other vertical shafts in multi-story buildings. Because the cable connects different floors of multi-story buildings, it must be designed to meet safety codes that specify a low level of flammability. Riser cables are also used in telephone company central offices to connect the equipment with the outside-plant cable, which enters a “vault,” which is usually below grade.

SDH

Synchronous digital hierarchy. The international standard for synchronous optical transmission, defined by CCITT to be technically comparable to the North American SONET standard. SONET and SDH technology has several consequences on the cable market. One is that add/drop multiplexers and other units of equipment have been developed for use in a cable system configured as a ring, which can mean more fibers per cable, or more route km to link two points. Also, SONET and SDH standards are defined for high bit rates where dispersion-modified fibers may be necessary, depending on the distance spanned.

SDV

Switched digital video. Refers to technology for providing video services in loop or distribution networks. Typically, SDV is associated with fiber-to-the-curb and contrasted with HFC networks. This contracts with HFC, which “broadcasts” the signal to all subscribers.

SONET

Synchronous optical network. A standard – or more specifically a set of standards – for synchronous transmission. The standards include signal rates, formats, and optical and electrical interface specifications. The standards organization is ANSI. The international counterpart of the SONET standards is SDH. See “SDH” for reference to the impact of SONET / SDH technology on cable markets.

Source

Short for “optical source.” Used to refer to a light source used with single-mode fiber—mainly to acknowledge that not all applications use lasers. Some use ELEDs. Therefore, the term “source” in most cases can be understood as “lasers plus ELEDs.

Switched access

Access to the switched network of an exchange for the purpose of originating or terminating communications. Switched access is available to carrier only.

Switching Equipment

Equipment that makes connections on a per-call basis between two or more circuits, services, or communications systems.

TDM

Time-division multiplexing. Signaling technology in which two or more signals can be transmitted over the same path by using different time slots or intervals for each signal. In telecommunications, this is done with digital signals so that packets from two or more lower-speed digital signals are interleaved into time slots on a higher-speed multiplexed signal. In TDM fiber optic systems, the digital signals are multiplexed electronically so that resulting aggregated or multiplexed high-bit-rate signal is transmitted over fiber as a single high-speed signal. After is it received and converted to an electronic signal, it is de-multiplexed electronically into the two (or more) original signals.

Telco

Telephone company. A term from the telephone industry jargon. It usually refers to a local exchange carrier but it is not precise and also can refer to long-distance carriers.

Tele-density

An indicator that shows the extent that a country’s telecommunications infrastructure has been built up to serve the country’s populace. It is usually expressed as the number of lines per 100 population.

Telephone network

A system of electronic switching devices, computers and lines that provide voice, data, and video communication among customers throughout the world.

Token ring

This IEEE transmission protocol standard connects each end user to a node, and transfers data packets around to each node on the ring network using a bus to avoid the collisions associated with Ethernet.

Transceiver

A module containing both a transmitter and receiver. A “transceiver” is an example of a “transmitter/receiver pair” but other examples have separate packaging for the transmitter and the receiver.

Trunk

Connections between telephone company offices or switch locations. The application usually is a long-distance application of fiber optics. The term also used in the CATV industry to refer to links between head-ends.

Twisted pair

Phone wiring consisting of two copper wires twisted around each other. Modern technology can load it up with lots of data and video over short distance. See TWP.

TWP

Twisted pair. Refers to a wide class of copper communication cables.

Tx/Rx pair

Transmitter/receiver pair. An abbreviation used to note the number of “transmitter/receiver pairs” in the market for a specific application or customer group. A transmitter/receiver pair consists of one transmitter (laser) plus one receiver (detector). They can be in a combined “transceiver” module or packaged separately.

Upstream

Transmission direction from the subscriber towards the central office or head end.

VCSEL

Vertical cavity surface-emitting laser. Refers to a laser diode structure designed to emit the optical radiation in a vertical direction relative to the plane with the active region. Most diode lasers emit from end facets in the plane of the active region.

VOD

Video on demand.

VPN

Virtual Private Network

WAN

Wide area network. Refers to a network that uses switched long-distance, dedicated, or leased facilities to link two or more locations in different cities for data or other applications.

WDM

Wavelength-division multiplexing. The simultaneous transmission of more than one optical signal through an optical fiber with each signal having a distinct wavelength. WDM technology is typically used to increase system capacity by adding channels at different wavelengths. WDM devices are the multiplexers that combine the multiple optical input channels into a single fiber and the de-multiplexers that separate the signals of different wavelengths at the receive end. See also “DWDM”.

Wire-line

Describes telecommunications network or links based on cable—either copper, coax, or fiber optic—to differentiate such networks from cellular, microwave, PCS, satellite or other “wireless” networks.

Zero Dispersion Wavelength

The wavelength at which a fiber’s chromatic dispersion equals zero.