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Microcom Networking Protocol
The Microcom Networking Protocols, almost always shortened to MNP, is a family of error-correcting protocols commonly used on early high-speed (2400 bit/s and higher) modems. Originally developed for use on Microcom's own family of modems, the protocol was later openly licensed and used by most of the modem industry, notably the "big three", Telebit, USRobotics and Hayes. MNP was later supplanted by v.42bis, which was used almost universally starting with the first v.32bis modems in the early 1990s. Overview Although Xmodem was introduced 1977, as late as 1985 ''The New York Times'' described XMODEM first, then discussed ''MNP'' as a leading contender, and that 9600 baud modems "are beginning to make their appearance." By 1988, the ''Times'' was talking about 9600 and 19.2K, and that "At least 100 other brands of modems follow" MNP (compared to Hayes' use of LAP-B). Error correction basics Modems are, by their nature, error-prone devices. Noise on the telephone line, a common oc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Modem
A modulator-demodulator or modem is a computer hardware device that converts data from a digital format into a format suitable for an analog transmission medium such as telephone or radio. A modem transmits data by Modulation#Digital modulation methods, modulating one or more carrier wave signals to encode digital information, while the receiver Demodulation, demodulates the signal to recreate the original digital information. The goal is to produce a Signal (electronics), signal that can be transmitted easily and decoded reliably. Modems can be used with almost any means of transmitting analog signals, from light-emitting diodes to radio. Early modems were devices that used audible sounds suitable for transmission over traditional telephone systems and leased lines. These generally operated at 110 or 300 bits per second (bit/s), and the connection between devices was normally manual, using an attached telephone handset. By the 1970s, higher speeds of 1,200 and 2,400 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dumb Terminals
A computer terminal is an electronic or electromechanical hardware device that can be used for entering data into, and transcribing data from, a computer or a computing system. The teletype was an example of an early-day hard-copy terminal and predated the use of a computer screen by decades. Early terminals were inexpensive devices but very slow compared to punched cards or paper tape for input, yet as the technology improved and video displays were introduced, terminals pushed these older forms of interaction from the industry. A related development was time-sharing systems, which evolved in parallel and made up for any inefficiencies in the user's typing ability with the ability to support multiple users on the same machine, each at their own terminal or terminals. The function of a terminal is typically confined to transcription and input of data; a device with significant local, programmable data-processing capability may be called a "smart terminal" or fat client. A term ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
BLAST (protocol)
BLAST (BLocked ASynchronous Transmission), like XMODEM and Kermit, is a communications protocol designed for file transfer over asynchronous communication ports and dial-up modems that achieved a significant degree of popularity during the 1980s. Reflecting its status as a de facto standard for such transfers, BLAST, along with XMODEM, was briefly under official consideration by ANSI in the mid-80s as part of that organization's ultimately futile attempt to establish a single de jure standard. Overview BLAST grew out of the mission-critical experience of providing air pollution telemetry within the dial-up communications environment of the petroleum belt of southern Louisiana and Texas, with not only noisy telephone lines but also unexpected satellite hops to remote locations.Smith, G. W. "Aesthetic Wilderness: A Brief Personal History of the Meeting Between Art and the Machine", Birds-of-the-Air Press, 2011. Estill, Lyle "Small is Possible: Life in a Local Economy", New Socie ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
ZModem
ZMODEM is an inline file transfer protocol developed by Chuck Forsberg in 1986, in a project funded by Telenet in order to improve file transfers on their X.25 network. In addition to dramatically improved performance compared to older protocols, ZMODEM offered restartable transfers, auto-start by the sender, an expanded 32-bit CRC, and control character quoting supporting 8-bit clean transfers, allowing it to be used on networks that would not pass control characters. In contrast to most transfer protocols developed for bulletin board systems (BBSs), ZMODEM was not directly based on, nor compatible with, the seminal XMODEM. Many variants of XMODEM had been developed in order to address one or more of its shortcomings, and most remained backward compatible and would successfully complete transfers with "classic" XMODEM implementations. This list includes Forsberg's own YMODEM. ZMODEM eschewed backward compatibility in favor of producing a radically improved protocol. It perfor ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
YModem
YMODEM is a file transfer protocol used between microcomputers connected together using modems. It was primarily used to transfer files to and from bulletin board systems. YMODEM was developed by Chuck Forsberg as an expansion of XMODEM and was first implemented in his CP/M YAM program. Initially also known as YAM, it was formally given the name "YMODEM" in 1985 by Ward Christensen, author of the original XMODEM. YMODEM extended XMODEM in three ways, combining features found in other extended XMODEM varieties. Like XMODEM-CRC, YMODEM replaced the 8-bit checksum with a 16-bit cyclic redundancy check (CRC), but made it the default form of correction instead of optional. From TeLink it added the "block 0" header that sent the filename and size, which allowed batch transfers (multiple files in a single session) and eliminated the need to add padding at the end of the file. Finally, YMODEM allowed the block size to be increased from the original 128 bytes of data to 1024, as in XMODEM ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Enhanced Throughput Cellular
''Enhanced'' is a 2019 Canadian-Japanese action film produced, written and directed by James Mark. The film premiered at the 2019 Toronto After Dark Film Festival. Plot A sinister government organization hunts down mutants, and one of such is a young woman with enhanced abilities. But when she encounters even stronger serial killer who emerges on the scene, agents and mutants are forced to question their allegiances. This is not an advertised sequel, but it is the continuation of the story from the 2017 movie "Kill Order". Cast *George Tchortov as George Shepherd *Alanna Bale as Anna * Adrian Holmes as captain Williams *Chris Mark as David * Eric Hicks as Scott *Michael Joseph Delaney as Eli *Patrick Sabongui as Joseph *Elvis Stojko as officer Reves *Stefano DiMatteo as Marco *Jeffrey R. Smith as Danny *Dorren Lee as Fanny *Eric Daniel as Mehran *Carl Bauer as Ritchie *Kevan Kase as Joey *Dylan Mask as Jim *Alain Moussi as Abel *Tyler James Williams as Ron *Mustafa Bulut as subjec ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rockwell International
Rockwell International was a major American manufacturing conglomerate involved in aircraft, the space industry, defense and commercial electronics, components in the automotive industry, printing presses, avionics and industrial products. Rockwell International's predecessor was Rockwell Manufacturing Company, founded in 1919 by Willard Rockwell. In 1968, Rockwell Manufacturing Company included 7 operating divisions manufacturing industrial valves, German 2-cycle motors, power tools, gas and water meters. In 1973, it was combined with the aerospace products and renamed Rockwell International. At its peak, Rockwell International was No. 27 on the Fortune 500 list, with assets of over $8 billion, sales of $27 billion and 115,000 employees. History Rockwell Manufacturing Company Boston-born Willard Rockwell (1888–1978) made his fortune with the invention and successful launch of a new bearing system for truck axles in 1919. He merged his Oshkosh, Wisconsin-base ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
CompuCom SpeedModem
The CompuCom SpeedModem was an early high speed modem that implemented a proprietary 9600 bit/s protocol known as the CompuCom Speed Protocol (CSP). Their modems were much less expensive than competing high-speed models, and were well known for a time. The introduction of low-cost standards-based v.32bis modems made the SpeedModem disappear with surprising speed. Two versions of the SpeedModem were released in 1991, the Champ with an introductory price of $169, and Combo at $279 which added 9,600 bit/s Group III fax support. The modem supported MNP5 data compression and their own format, CSP-3, which they claimed was as effective as v.42bis. For connections to other modems, the SpeedModem supported V.22bis for 2400 bit/s support (as well as 1200 and 300 bit/s support)."Com ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
SupraFAXModem 14400
The SupraFAXModem 14400 was a v.32bis modem. When it was launched by Supra, Inc. in January 1992 at a $399 price point,Difference sources list the price between $349 and $399 the 14,400 bit/s model was less expensive than most existing 9600 bit/s models. This price/performance ratio made it a disruptive technology, and its introduction drove modem prices sharply downward. Whereas a 9600 bit/s modem was perhaps $599 only a month before its introduction; by the end of the year $250 14400 bit/s modems were not uncommon. Background Supra had been a small player in the computer market through the mid-to-late 1980s, known originally for their external hard drives for the Atari ST and a variety of follow-on products. During 1991, Rockwell International's chip-making arm developed a new modem driver chipset that included all of the latest standards that were then under development. Supra, never having been known as a "player" in the modem world, designed a modem based on the new ch ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
LAPM
Link Access Procedure for Modems (LAPM) is part of the V.42 error correction protocol for modems.ITU-T Recommendation V.42Error-correcting procedures for DCEs using asynchronous-to-synchronous conversion/ref> LAPM is an error control protocol defined in ITU-T recommendations V.42. Like many data link layer protocols, it is a variant of HDLC. Like the Microcom Networking Protocols that preceded it, LAPM uses cyclic redundancy checking (CRC) and retransmission of corrupted data (ARQ) to ensure data reliability. Error control protocols such as LAPM use frames of variable lengths, each beginning with a header and ending with a frame check sequence trailer (a cyclic redundancy check). Correctly received packets are acknowledged, and unacknowledged packets are automatically retransmitted ( ARQ). The larger the payload included in each frame, the smaller the relative cost of transmitting the header and trailer bits. Usually LAPM adds only about 5 percent framing overhead. This is a no ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bulletin Board System
A bulletin board system (BBS), also called computer bulletin board service (CBBS), is a computer server running software that allows users to connect to the system using a terminal program. Once logged in, the user can perform functions such as uploading and downloading software and data, reading news and bulletins, and exchanging messages with other users through public message boards and sometimes via direct chatting. In the early 1980s, message networks such as FidoNet were developed to provide services such as NetMail, which is similar to internet-based email. Many BBSes also offer online games in which users can compete with each other. BBSes with multiple phone lines often provide chat rooms, allowing users to interact with each other. Bulletin board systems were in many ways a precursor to the modern form of the World Wide Web, social networks, and other aspects of the Internet. Low-cost, high-performance asynchronous modems drove the use of online services and BBSes t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Data Compression
In information theory, data compression, source coding, or bit-rate reduction is the process of encoding information using fewer bits than the original representation. Any particular compression is either lossy or lossless. Lossless compression reduces bits by identifying and eliminating statistical redundancy. No information is lost in lossless compression. Lossy compression reduces bits by removing unnecessary or less important information. Typically, a device that performs data compression is referred to as an encoder, and one that performs the reversal of the process (decompression) as a decoder. The process of reducing the size of a data file is often referred to as data compression. In the context of data transmission, it is called source coding; encoding done at the source of the data before it is stored or transmitted. Source coding should not be confused with channel coding, for error detection and correction or line coding, the means for mapping data onto a signal. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
