Conrad L. Young’s Wired Broadband and Related Industry Glossary of Terms with Acronyms As of 15 February 2012 Open Access This document is distributed under the terms of the Creative Commons Attribution Noncommercial License which permits any noncommercial
A photo detector (PD) specification denoted by t
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A photo detector (PD) specification denoted by tr, describing the time required for a PD to begin producing electrical output from receipt of optical energy at its input. (Zanger) 
Pulse Waveform Diagram courtesy of Fiber Optics Info, http://www.fiber-optics.info/fiber_optic_glossary/r Rivest Cipher 4 (RC4) A variable length stream cipher. Optionally used to encrypt the media traffic in PacketCable. RJ Random Jitter (FiberOpticsInfo) RJ-11 Jack/Connector An RJ-11 connector is the small, modular plug used for most analog telephones. It has six pin slots in the head, but usually only two or four of them are used. 
RJ-11 Photo courtesy of Your Dictionary dot com, http://images.yourdictionary.com/rj-11 RJ-45 Jack/Connector An RJ-45 connector is similar in appearance to a modular RJ-11 connector, but is wider and has eight-pin slot positions instead of six. RJ-45 connectors are used to connect ISDN S/T Interfaces and for 10-Base-T, 100Base-T, or 1000Base-T Ethernet cabling. 
RJ-45 Photo courtesy of Your Dictionary dot com, http://images.yourdictionary.com/rj-11 RKS Record Keeping Server RMI Remote Method Invocation RMS Rights Management System RMS Root Mean Square; technique used to measure AC voltages. (FiberOpticsInfo) RMS Rotary Mechanical Splice Roadblocking The practice of stripping commercials in designated time periods across multiple cable channels. Can be an effective method for catching channel surfers. ROADM Reconfigurable Optical Add/Drop Multiplexer; a passive device that can add, block, pass or redirect modulated infrared (IR) and visible light beams of various wavelengths in a fiber optic network. ROADMs are used in systems that employ wavelength division multiplexing. Before the development of optical multiplexing devices such as ROADMs, signal routing in fiber optic networks was done by converting the IR or visible beams to electrical signals and routing those signals using conventional electronic switches. The rerouted electrical signals were then converted back into IR or visible beams. In a conventional ROADM, switching is accomplished without optical-to-electrical or electrical-to-optical conversion using three operations called add, drop and cut-through. An outgoing IR or visible beam can be generated (the add operation) or an incoming beam terminated (the drop operation). A beam can also be passed through the device without modification (the cut-through operation). In combination, these functions allow optical signal routing of considerable complexity. The configuration of the system can be changed remotely. Two major ROADM technologies are in current use. They are called wavelength blocking (WB) and planar light-wave circuit (PLC). Wavelength blocking, also called first-generation ROADM technology is the older of the two. When a wavelength change is necessary for a particular channel, the IR or visible light beam at the original wavelength is filtered out and its data extracted. Then the data is impressed onto a beam of another wavelength. PLC or second-generation ROADM technology in effect combines these steps, streamlining the process and reducing the cost. Neither the WB nor the PLC ROADM designs facilitate true optical branching, in which beams of any wavelength can be directly routed to any desired port without the need to perform multiple intermediate operations. Optical branching capability is important in the deployment of efficient, reliable, high-volume optical networks designed to provide advanced services such as video on demand (VoD). An evolving technology called enhanced ROADM (eROADM) makes true optical branching possible. (SearchTelecom) 
ROADM Diagram courtesy of International Engineering Consortium, http://www.iec.org/newsletter/jan06_2/broadband_1.html RoF Radio over Fiber; refers to a technology whereby light is modulated by a radio signal and transmitted over an optical fiber link to facilitate wireless access. Although radio transmission over fiber is used for multiple purposes, such as in cable television (CATV) networks and in satellite base stations, the term RoF is usually applied when this is done for wireless access. In RoF systems, wireless signals are transported in optical form between a central station and a set of base stations before being radiated through the air. Each base station is adapted to communicate over a radio link with at least one user's mobile station located within the radio range of said base station. RoF transmission systems are usually classified into two main categories (RF-over-Fiber; IF-over-Fiber) depending on the frequency range of the radio signal to be transported. (Wikipedia) a) In RF-over-Fiber architecture, a data-carrying RF (Radio Frequency) signal with a high frequency (usually greater than 10 GHz) is imposed on a lightwave signal before being transported over the optical link. Therefore, wireless signals are optically distributed to base stations directly at high frequencies and converted to from optical to electrical domain at the base stations before being amplified and radiated by an antenna. As a result, no frequency up/down conversion is required at the various base station, thereby resulting in simple and rather cost-effective implementation is enabled at the base stations. b) In IF-over-Fiber architecture, an IF (Intermediate Frequency) radio signal with a lower frequency (less than 10 GHz) is used for modulating light before being transported over the optical link. Therefore, wireless signals are transported at intermediate frequency over the optical. Roll A loss of vertical synchronization which causes the picture to move up or down on receiver or monitor. (Channel Vision) Roll-Off A gradual attenuation of gain-frequency response at either or both ends of the transmission pass band. ROM Read Only Memory R-ONU RF over Glass (RFoG) Optical Network Unit; device defined by SCTE 174 2010, “Radio Frequency over Glass Fiber-to-the-Home Specification”. The RFoG system is defined to terminate at the subscriber-side interface of an RFoG Optical Network Unit (R-ONU) at the home. The specifications in SCTE 174 2010 apply to the RFoG Optical Network Unit (R-ONU) and are designed to allow interoperability between R-ONUs from various manufacturers. (SCTE) Root Private Key The private signing key of the highest-level Certification Authority. It is normally used to sign public key certificates for lower-level Certification Authorities or other entities. Root Public Key The public key of the highest level Certification Authority, normally used to verify digital signatures generated with the corresponding root private key. ROSI Return On Security Investment Rotating Coupler The portion of a connector that rotates freely, making it unnecessary to twist the entire connector (as well as any devices attached to the connector) during installation. (Arris Glossary of Terms) Router Routers are special network devices used to connect one recognized computer network to another. Routers work like a postal worker; they examine the To addresses of network messages they are given and use part of the address like a zip code to figure out which computer network to send it to. Once a router has figured out which network the message should go to, it sends the message to another router, which repeats the process until the last router in the chain sends it directly to the computer listed in the destination address. Most WANs use routers to connect one LAN location to another. Routing Information Protocol (RIP) A protocol of the Internet Engineering Task Force (IETF) for exchanging routing information about Internet Protocol (IP) networks and subnets. RS-250C An ANSI recommended standard for video transmission used to evaluate the quality of a received picture quality. Different requirements exist for short-haul, medium-haul, and long-haul RS-250C. Each of these three levels is defined by the number of intermediate processing devices and the type of path (optical or electrical). (FiberOpticsInfo) RSA A public-key, or asymmetric, cryptographic algorithm that is used to provide the services of authentication and encryption. RSA stands for the three inventors of the algorithm; Rivest, Shamir, Adleman; also company by same name marketing public key technology. RSA Key Pair A public/private key pair created for use with the RSA cryptographic algorithm. RSVP Resource reSerVation Protocol RTP/RTCP Real-time Protocol/Real-time Control Protocol RTCP Real-time Control Protocol RTP Real Time Protocol RTS Request to Send; in a communications network, a signal from a remote receiver to a transmitter for data to be sent to that receiver. (FiberOpticsInfo) RTSP Real Time Streaming Protocol RZ Return to Zero; a common means of encoding data that has two information states called “zero” and “one” in which the signal returns to a rest state during a portion of the bit period. (FiberOpticsInfo) S: SA Security Association
The reversal of a developed image due to the exposure of the partially developed image to actinic light. (Photonics dot com) Saccadic Motion The movement of the eye as it focuses on details of a scene. Some imaging systems mimic this movement by small, rapid scanning motions of the sensor. (Photonics dot com) Saccharimeter A special-purpose polarimeter having a scale calibrated directly in the concentration of sugar in the test solution. (Photonics dot com) Saddle A term used to describe a saddle-shaped -- i.e., convex along one axis, concave along the other -- polished surface, generally an error, whose contours are apparent by the shape of Newton's rings. (Photonics dot com) Saha Equation Formula that describes the thermal equilibrium of gas electrons and ions as a direct function of variations in temperature. (Photonics dot com) Sagnac Interferometer A Sagnac interferometer (named after the French physicist Georges Sagnac) uses counterpropagating beams in a ring path, realized e.g. with multiple mirrors or with an optical fiber. If the whole interferometer is rotated e.g. around an axis which is perpendicular to the drawing plane, this introduces a relative phase shift of the counterpropagating beams (Sagnac effect). The sensitivity for rotations depends on the area covered by the ring, multiplied by the number of round trips (which can be large e.g. when using many turns in an optical fiber). It is possible e.g. to obtain a sensitivity which is sufficient for measuring the rotation of the Earth around its axis. Sagnac interferometers are used in inertial guidance systems. (Encylopedia of Laser Physics and Technology) 
Sagnac interferometer. SAID Security Association Identifier Sample In analog to digital signal processing; a sample is taken at regular intervals to establish the electrical potential (voltage) present in an analog system at a given point in time. Each sample is then assigned a digital value. In telephony, sample values are established by a codex, and range from zero to 255. (Though, for most “voice grade” connections the actual range of codex values is between zero and 127). Each sample value is transmitted across the digital phone network and used to re-create a facsimile of the original analog signal at the other end of a phone connection. Sample and Hold Circuit A device that acquires a signal and then stores it for a specified period of time before processing, and used, for example, to reduce noise as in correlated double sampling. (Photonics dot com) Sample Rate In analog to digital signal processing, the sample rate is the interval at which samples of an analog signal are taken. The sample rate for digital telephony, for example, is 8000 per second. Sandbox Unsigned applications and signed applications without a permission file have access to all the APIs for which there is no permission signaling defined. This is commonly called the sandbox. SAP Second Audio Program SAP Service Access Point SAR Specific Absorption Rate, a measure of the amount of RF power absorbed in any part of the human body due to the use of equipment such as mobile phones or by human exposure close to other transmitting sources. (TETRA) SARFT The State Administration of Radio Film Television; an executive branch under the State Council of the People's Republic of China (PRC). Its main task is the administration and supervision of state-owned enterprises engaged in the television, radio, and film industries. The SARFT directly controls state-owned enterprises at the national level such as China Central Television, China National Radio, China Radio International, as well as other movie and television studios and other non-business organizations. The SARFT plays a similar role in China as TDF Group plays in France and Germany, or Crown Castle plays in the US or Australia. The SARFT owns and operates, as well as manages many thousands of microwave (MW), FM, TV and Shortwave relay transmitters in PRC (as well as those leased abroad for external broadcasting). The SARFT is also responsible for censoring any materials that might be objective to Chinese government or cultural standards. (Wikipedia) Satellite Device located in geostationary orbit above the earth which receives transmissions from separate points and retransmits them to cable systems, Direct Broadcast Satellite (DBS) receivers, and others over a wide area. Satellite Bands Frequency ranges used in satellite communications. (PC Magazine Encyclopedia)
Satellite Dish Antenna A system for concentrating the weak signals sent from a satellite. Satellite Downlink A data service that broadcasts data from an orbital satellite to terrestrial receivers. Used by some satellite TV vendors to provide a high-speed feed for receiving data from the Internet. Data sent to the Internet (Web page requests, outbound e-mail, etc.) must be sent by more conventional means, such as a dial-up modem connections to a local ISP. Satellite Master Antenna Television System (SMATV) Systems that serve a concentration of TV sets such as an apartment building, hotel, etc., utilizing one central antenna to pick up broadcast and/or satellite signals. Or RF distribution of satellite and antenna signals. Satellite Receiver An electronic device capable of receiving satellite transmitted signals, downconverting and demodulating those signals, and providing a baseband output. (Arris Glossary of Terms) Satellite Terminal A receive-only satellite earth station consisting of an antenna reflector (typically parabolic in shape), a feedhorn, a low-noise amplifier (LNA), a down converter and a receiver. (Satnews) Saticon A direct-readout television pickup tube. (Photonics dot com) Saturable Absorber A laser dye whose absorption coefficient drops at high levels of incident radiation. The phenomenon is often called bleaching. (Photonics dot com) Saturation 1) In a communications system, the condition in which a component of the system has reached its maximum traffic handling capacity. 2) The point at which the output of a linear device, such as a linear amplifier, deviates significantly from being a linear function of the input when the input signal is increased. 3) The degree of the chroma or purity of a color. (FiberOpticsInfo) Savart Plate A double-plate device used to transmit polarized light and form interference fringes of the light, thus indicating its presence. It consists of two calcite plates of equal thickness, cut parallel to their natural cleavage faces and rotated and cemented together so that one is at right angles to the other. (Photonics dot com) Savart Polariscope 1. A polariscope consisting of a Savart plate and a tourmaline plate analyzer, and used to produce parallel color fringes by transmitting polarized light. 2. A polariscope composed of an analyzing prism and Savart plate, and used with a theodolite to determine the neutral points of a source. (Photonics dot com) SAW (Surface Acoustic Wave) Filter A solid state filter that yields a sharp transition between regions of transmitted and attenuated frequencies. (Arris Glossary of Terms) S-Band The wavelength region between 1485 nm and 1520 nm used in some CWDM and DWDM applications. (FiberOpticsInfo) SBS Stimulated Brillouin Scattering; Brillouin scattering, named after Léon Brillouin, occurs when light in a medium (such as air, water or a crystal) interacts with time dependent optical density variations and changes its energy (frequency) and path. The density variations may be due to acoustic modes, such as phonons, magnetic modes, such as magnons, or temperature gradients. As described in classical physics, when the medium is compressed its index of refraction changes, and a fraction of the traveling light wave, interacting with the periodic refraction index variations, is deflected as in a three-dimensional diffraction grating. Since the sound wave, too, is travelling, light is also subjected to a Doppler shift, so its frequency changes. From a quantum point of view, Brillouin scattering is an interaction of light photons with acoustic or vibrational quanta (phonons), magnetic spin waves (magnons), or other low frequency quasiparticles interacting with light. The interaction consists of an inelastic scattering process in which a phonon or magnon is either created (Stokes process) or annihilated (anti-Stokes process). The energy of the scattered light is slightly changed, that is decreased for a Stokes process and increased for an anti-Stokes process. This shift, known as the Brillouin shift, is equal to the energy of the interacting phonon or magnon and thus Brillouin scattering can be used to measure phonon or magnon energies. The Brillouin shift is commonly measured by the use of a Brillouin spectrometer based on a Fabry–Pérot interferometer. (Wikipedia) SBS is a non-linear impairment that limits the maximum optical transmitted power that can be launched within a single-mode fiber (SMF), such as SMF-28, widely used within cable HFC networks and PON. The SBS threshold (SBSt) of ITU-T G.652 compliant SMF-28 is between +6 and +7 dBm at 1550nm wavelength. SBS bandwidth within SMF is approximately 20 MHz. Phase modulation of the optical transmitter is used to increase SBSt to approximately +16 dBm optical launch power using G.652 SMF-28 at 1550nm without suffering excessive CNR and CSO penalties. SBSt can also be increased through the use of fiber optic cable with greater than standard SBSt, such as Corning “G.652+” which offers a +3 dBm improvement in SBSt versus standard G.652 fiber at 1550nm. Another commonly employed technique within cable HFC networks and PONs is to launch high transmit optical power (e.g., from an Erbium Doped Fiber Amplifier (EDFA)) directly into a passive optical splitter. The passive optical splitter insertion loss helps to limit optical launch power to a level below SBSt. (Weiss) SC Fiber optic molded plastic connector. The SC connector is a fiber optic connector with a push-pull latching mechanism which provides quick insertion and removal while also ensuring a positive connection. SC is an abbreviation for Subscriber Connector. The SC connector is also available in a duplex configuration. SC connector has a benefit in keyed duplex capability to support send/receive channels. These connectors are commonly used for most modern network applications. The SC is a snap-in connector that is extensively used in single-mode systems for its remarkable efficiency. They are inexpensive, trouble-free, and robust. SC connectors give precise positioning via their ceramic ferrules. The square, snap-in connector latches with a simple push-pull motion and is keyed. They feature a 2.5mm ferrule and molded housing for shielding. Characteristically compared SC connectors are known for 1000 mating cycles and have an insertion loss of 0.25 dB. The SC connector has been standardized as FOCIS 3 (Fiber Optic Connector Intermateability Standards) in EIA/TIA-604-03. (Tech-FAQ (Copyrighted))
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