0-9  A  B  C  D  E  F  G  H  I  J  K  L  M  N  O  P  Q  R  S  T  U  V  W  X  Y  Z backbone A segment of a network used to connect smaller segments of networks together. Backbones carry a high concentration of traffic between smaller segments of networks. The backbone may interconnect multiple locations in a large geographic area or a number of smaller networks in a single location. When a number of networks are joined in a single device, such as a router, this capability is referred to as a collapsed analog. back-end loaded Refers to a greater proportion of revenues or other metric recognized at the end of the period than at the front of a period. backhaul High-speed data transmission from a cellular base station to the trunking network. A traffic management technique of routing data through an alternative POP to its destination for expense reasons. band The frequency spectrum between two defined limits. bandwidth The carrying capacity or size of a communications channel, usually expressed in hertz for analog circuits (the original means of the term), and in bits per second (bps) for digital circuits. The transmission speed is measured in bits per second (1 Kbps = 1,000 bits, 1 Mbps = 1,000 kilobits, 1 Gbps = 1,000 Mbps). barrier to entry Describes characteristics that make it difficult for new competitors to enter an existing playing field. Barrier to entry may lead to higher valuations due to the ability of the company to maintain higher market share and reduce pressure on margins that are commonly associated with increased competition. Examples include economies of scale, brand equity, large capital requirements, and government policies. basic EPS Earnings per share of common stock that is calculated by dividing earnings available to common stockholders (i.e., net income) divided by the number of issued outstanding shares of common stock. It is used to measure the economic benefit to shareholders on a per share basis over a given period of the company's operating history. The figure is compared to prior and forecasted future periods and to comparable companies performances. It is only used in cases in which the company has negative earnings; otherwise, diluted EPS is used. beam splitter A device for dividing an optical beam into two or more separate beams. An example of a beam splitter is a partially reflecting mirror. beta A quantitative measure of the volatility of a stock in relation to the rest of the stock market. The S&P 500 has a beta of 1 and is generally used as a measure to represent the overall market. A security with a beta greater than one is expected to rise and fall at a faster rate than the overall market, whereas the opposite is true for a beta below 1. An investor with a higher risk tolerance may be willing to accept investments with higher betas, which are generally expected to have higher associated returns, while lower betas have lower expected returns (see Capital Asset Pricing Model). bi-directional Operating in both directions. Bi-directional APS allows protection switching to be initiated by either end of the line. binary The base-2 number system using only the symbols 0 and 1. Since 0 and 1 can be represented as on and off, or negative and positive charges, most computers do their calculations in binary format. bit Short for binary digit. Either 1 or 0 in the binary number system, a bit represents the smallest unit of information in the binary system of notation. One binary digit is equivalent to one pulse of data. A bit is also the smallest element of a computer program. See byte. bit-error rate In data communications testing, the ratio between the total number of bits transmitted in a given message and the number of bits in that message received in error. A measure of the quality of the data transmission, it usually is expressed as a number referred to a power of 10 (e.g., 1 in 10 over  5). blocking This occurs when an optical signal in a network is intercepted by an electronic device and therefore does not pass unhindered through the network. broadband loop emulation service (BLES) (DSL Forum) Bluetooth Named for the 10th-century Danish king who unified Denmark, Bluetooth is a code name for a proposed open specification to standardize data synchronization between disparate handheld and PC devices. The goal for Bluetooth is to act as a virtual cable, linking equipment from different vendors within a short range. For example a personal digital assistant using a Bluetooth connection could send data wirelessly to a fax in the same room. Bluetooth uses an FM modulation combined with frequency hopping technique to connect disparate devices within a range of 10 meters at a speed of 1Mbps. Bluetooth radios operate in the 2.4 GHz range of unlicensed spectrum. board of advisors The Board of Advisors serves to provide strategic and operational advice as well as to provide external contacts to a company. This is especially valuable to a smaller company, which may require additional expertise and crucial guidance on the direction of the business. A company may have both a Board of Directors and Board of Advisors, although the latter does not typically have any legal or fiduciary responsibility. board of directors A group of individuals elected by the shareholders, to represent the rights and interests of the shareholders. It is responsible for setting company policy and carrying out tasks in the corporate charter, such as "appointing senior management, naming members of executive and finance committees (if any), issuing additional shares and declaring dividends." (Barron's Financial Guides, "Dictionary of Finance and Investment Terms," Fourth Edition, 1995). The board usually includes members of top management ("inside directors") and members chosen from the business community ("outside directors"). The chief executive officer (CEO) reports directly to the Board of Directors, which is ultimately accountable to the shareholders. book value Book Value is equal to total assets minus intangible assets (e.g. goodwill, etc.) less liabilities (including preferred stock) and generally represents the original price of the asset. Book Value may refer to physical assets such as property, plant, and equipment. The lesser of market value and book value is recorded on the financial statements as a conservative value of the assets. Book Value often differs substantially from market value, especially in knowledge industries with a high proportion of intangible assets such as the high-tech industry. Book Value can also be used as a general floor to stock valuation, since most companies trade at or above their Book Value. border gateway protocol (BGP) An external gateway protocol that defines how routers exchange information between multiple autonomous systems in order to deliver data packets using the optimal routing path. bragg grating See fiber bragg gratings. broadband A data-transmission scheme in which multiple signals share the bandwidth of a medium. This allows the transmission of voice, data, and video signals over a single medium. broadband and IP data services company Next-generation communication service provider that either deploys or leverages the communications capabilities afforded by broadband-enabling technologies or IP-based protocols. Many service providers offer a mixture of all three capabilities or function as a distributor of services. broadband wireless Wireless transmission at high speed. Wireless transmission is slower than wireline speeds, thus, whereas land-based broadband is generally at T1 rates and above, wireless might be considered broadband at 250 Kbps and above. broadband wireless access (BWA) Broadband wireless access can best be described through each of its constituent terms. The Federal Communications Commission has defined broadband as two-way speeds of 200 kbps and above. Wireless services can render value by offering users mobility or by offering users inexpensive and rapid deployment to fixed stations. Access refers to the connection and associated electronics that link a core network to Internet points of presence (POPs) and switching locations (i.e., the central offices). This is also referred to as the "local loop," "subscriber loop," and "last mile." Broadband wireless access equipment is high-speed (fixed) wireless equipment designed to address the bandwidth bottleneck of the local loop. BWA equipment uses high-frequency signals to send and receive voice, data, and video wirelessly between hubs located in the center of cells and antennas on subscribers' premises. bus A common pathway, or channel, between multiple devices. A computer's internal bus is known as the local bus, or processor bus. It provides a parallel data transfer path between the central processing unit (CPU) and main memory to the peripheral buses. A 16-bit bus transfers two bytes at a time over 16 wires; a 32-bit bus uses 32 wires, etc. The bus is comprised of two parts: the address bus and the data bus. Addresses are sent over the address bus to signal a memory location, and data is transferred over the data bus to that location. The term was was meant to invoke a real bus, with the idea that a bus stops at all the bus-stops en route. In an electronic bus, the signals go to all stations connected to it. business-to-business (B-to-B) Refers to transactions that occurs between businesses. business-to-consumer (B-to-C) Refers to transactions that occurs between businesses and consumers. byte A set of bits of a certain length, usually 7 or 8, representing a value in a coding scheme. A byte is to a bit what a word is to a letter.