|
Hayes Communications
Hayes Microcomputer Products was a US-based manufacturer of modems. The company is known for the Smartmodem, which introduced a control language for operating the functions of the modem via the serial interface, in contrast to manual operation with front-panel switches. This ''smart modem'' approach dramatically simplified and automated operation. Today almost all modems use a variant of the Hayes AT command set. Hayes was a major brand in the modem market from the introduction of the original 300 bit/s Smartmodem in 1981. They remained a major vendor throughout the 1980s, periodically introducing models with higher throughput. Their competition through this period was primarily from two other high-end vendors, USRobotics and Telebit, while other companies mostly sold into niches or were strictly low-end offerings. In the early 1990s a number of greatly cost-reduced high-performance modems were released by competitors, notably the SupraFAXModem 14400 in 1992, which eroded price ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Public Company
A public company is a company whose ownership is organized via shares of share capital, stock which are intended to be freely traded on a stock exchange or in over-the-counter (finance), over-the-counter markets. A public (publicly traded) company can be listed on a stock exchange (listing (finance), listed company), which facilitates the trade of shares, or not (unlisted public company). In some jurisdictions, public companies over a certain size must be listed on an exchange. In most cases, public companies are ''private'' enterprises in the ''private'' sector, and "public" emphasizes their reporting and trading on the public markets. Public companies are formed within the legal systems of particular states and so have associations and formal designations, which are distinct and separate in the polity in which they reside. In the United States, for example, a public company is usually a type of corporation, though a corporation need not be a public company. In the United Kin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
McKesson Corporation
McKesson Corporation is a publicly traded American company that distributes Medication, pharmaceuticals and provides health information technology, Medical device, medical supplies, and Health administration, health management tools. The company delivers a third of all pharmaceutical products used or consumed in North America and employs over 80,000 employees. With $308.9 billion in 2024 revenue, it is the Fortune 500, ninth-largest company by revenue in the United States and the nation's largest health care company. The company is headquartered in Irving, Texas. It is a component of the S&P 500 and is listed on the New York Stock Exchange, where it is traded under the ticker symbol "MCK". McKesson provides extensive network of infrastructure for the healthcare industry and was an early adopter of technologies, including barcode scanning for distribution, pharmacy automation, pharmacy robotics, and Radio-frequency identification, RFID tags. The company has been named in a federal ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Computer Bus
In computer architecture, a bus (historically also called a data highway or databus) is a communication system that transfers data between components inside a computer or between computers. It encompasses both hardware (e.g., wires, optical fiber) and software, including communication protocols. At its core, a bus is a shared physical pathway, typically composed of wires, traces on a circuit board, or busbars, that allows multiple devices to communicate. To prevent conflicts and ensure orderly data exchange, buses rely on a communication protocol to manage which device can transmit data at a given time. Buses are categorized based on their role, such as system buses (also known as internal buses, internal data buses, or memory buses) connecting the CPU and memory. Expansion buses, also called peripheral buses, extend the system to connect additional devices, including peripherals. Examples of widely used buses include PCI Express (PCIe) for high-speed internal connectio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Novation CAT
Novation, Inc., is an early modem manufacturer whose CAT series were popular in the early home computer market in the late 1970s and early 1980s, notably on the Apple II. The Hayes Microcomputer Products, Hayes Smartmodem 300, introduced in 1981, helped kill off Novation and many other early modem companies over the next few years. The Original CAT Novation's first CAT was an external 300 bit/s Bell 103-standard modem that connected to the phone lines using an acoustic coupler. Like most other acoustically coupled modems, the CAT required the user to dial the desired number on a normal telephone, listening to the call connecting and the eventual presence of an answer tone. If the dialling was successful, the user then pressed the handset down into rubber cups on the modem to connect. This was only possible because telephones were generally available only from Western Electric, all of a standardized size and layout. There was no sort of automated operation available; even hangin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
On-hook
In telephony, on-hook and off-hook are two states of a communication circuit. On subscriber telephones the states are produced by placing the handset onto or off the hookswitch. Placing the circuit into the off-hook state is also called ''seizing the line''. ''Off-hook'' originally referred to the condition that prevailed when telephones had a separate earpiece (''receiver''), which hung from its switchhook until the user initiated a telephone call by removing it. When off hook the weight of the receiver no longer depresses the spring-loaded switchhook, thereby connecting the instrument to the telephone line. Off-hook The term off-hook has the following meanings: * The condition that exists when a telephone or other User (telecommunications), user instrument is in use, i.e., during Dialling (telephony), dialing or communicating. * A general description of one of two possible Signaling (telecommunications), signaling states at an interface between telecommunications systems, such ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Center Frequency
In electrical engineering and telecommunications, the center frequency of a filter or channel is a measure of a central frequency between the upper and lower cutoff frequencies. It is usually defined as either the arithmetic mean or the geometric mean of the lower cutoff frequency and the upper cutoff frequency of a band-pass system or a band-stop system. Typically, the geometric mean is used in systems based on certain transformations of lowpass filter designs, where the frequency response is constructed to be symmetric on a logarithmic frequency scale. The geometric center frequency corresponds to a mapping of the DC response of the prototype lowpass filter, which is a resonant frequency sometimes equal to the peak frequency of such systems, for example as in a Butterworth filter. The arithmetic definition is used in more general situations, such as in describing passband telecommunication systems, where filters are not necessarily symmetric but are treated on a linear fr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mainframe Computer
A mainframe computer, informally called a mainframe or big iron, is a computer used primarily by large organizations for critical applications like bulk data processing for tasks such as censuses, industry and consumer statistics, enterprise resource planning, and large-scale transaction processing. A mainframe computer is large but not as large as a supercomputer and has more processing power than some other classes of computers, such as minicomputers, server (computing), servers, workstations, and personal computers. Most large-scale computer-system architectures were established in the 1960s, but they continue to evolve. Mainframe computers are often used as servers. The term ''mainframe'' was derived from the large cabinet, called a ''main frame'', that housed the central processing unit and main computer memory, memory of early computers. Later, the term ''mainframe'' was used to distinguish high-end commercial computers from less powerful machines. Design Modern mainfr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Minicomputer
A minicomputer, or colloquially mini, is a type of general-purpose computer mostly developed from the mid-1960s, built significantly smaller and sold at a much lower price than mainframe computers . By 21st century-standards however, a mini is an exceptionally large machine. Minicomputers in the traditional technical sense covered here are only small relative to generally even earlier and much bigger machines. The class formed a distinct group with its own software architectures and operating systems. Minis were designed for control, instrumentation, human interaction, and communication switching, as distinct from calculation and record keeping. Many were sold indirectly to original equipment manufacturers (OEMs) for final end-use application. During the two-decade lifetime of the minicomputer class (1965–1985), almost 100 minicomputer vendor companies formed. Only a half-dozen remained by the mid-1980s. When single-chip CPU microprocessors appeared in the 1970s, the defi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Acoustic Coupler
In telecommunications, an acoustic coupler is an interface device for coupling electrical signals by acoustical means—usually into and out of a telephone. The link is achieved through converting electric signals from the phone line to sound and reconverting sound to electric signals needed for the end terminal, such as a teletypewriter, and back, rather than through direct electrical connection. History and applications Prior to its breakup in 1984, Bell System's legal monopoly over telephony in the United States allowed the company to impose strict rules on how consumers could access their network. Customers were prohibited from connecting equipment not made or sold by Bell to the network. The same set-up was operative in nearly all countries, where the telephone companies were nationally owned. In many households, telephones were hard-wired to wall terminals before connectors like RJ11 and BS 6312 became standardized. The situation was similar in other countries. I ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Home Computer
Home computers were a class of microcomputers that entered the market in 1977 and became common during the 1980s. They were marketed to consumers as affordable and accessible computers that, for the first time, were intended for the use of a single, non-technical user. These computers were a distinct market segment that typically cost much less than business, scientific, or engineering-oriented computers of the time, such as those running CP/M or the IBM PC, and were generally less powerful in terms of computer memory, memory and expandability. However, a home computer often had better video display controller, graphics and sound than contemporary business computers. Their most common uses were word processing, playing video games, and computer programming, programming. Home computers were usually sold already manufactured in stylish metal or plastic enclosures. However, some home computers also came as commercial electronic kits, like the ZX80, Sinclair ZX80, which were both h ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
8-bit Computer
In computer architecture, 8-bit integers or other data units are those that are 8 bits wide (1 octet). Also, 8-bit central processing unit (CPU) and arithmetic logic unit (ALU) architectures are those that are based on registers or data buses of that size. Memory addresses (and thus address buses) for 8-bit CPUs are generally larger than 8-bit, usually 16-bit. 8-bit microcomputers are microcomputers that use 8-bit microprocessors. The term '8-bit' is also applied to the character sets that could be used on computers with 8-bit bytes, the best known being various forms of extended ASCII, including the ISO/IEC 8859 series of national character sets especially Latin 1 for English and Western European languages. The IBM System/360 introduced byte-addressable memory with 8-bit bytes, as opposed to bit-addressable or decimal digit-addressable or word-addressable memory, although its general-purpose registers were 32 bits wide, and addresses were contained in the lower 24 bits of th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
