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Error Correction Mode
Error correction mode (ECM) is an optional transmission mode built into Class 1/2/2.0 fax machines or fax modems. ECM automatically detects and corrects errors in the fax transmission process that are sometimes caused by telephone line noise Noise is unwanted sound considered unpleasant, loud or disruptive to hearing. From a physics standpoint, there is no distinction between noise and desired sound, as both are vibrations through a medium, such as air or water. The difference arise .... The page data is divided into what is known as Octets (small blocks of data). Once the receiver has received all the Octets it examines them (using check-sums) and then advises the transmitting fax of any Octets that are in error. The transmitter then need only resend the blocks in error rather than the whole page. This generally means an ECM coded fax will be more likely to succeed in transmitting a copy of the page(s) on a noisy line. ECM is the norm rather than the exception. Some fax ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Transmission Mode
Transmission may refer to: Medicine, science and technology * Power transmission ** Electric power transmission ** Propulsion transmission, technology allowing controlled application of power *** Automatic transmission *** Manual transmission *** Electric transmission (propulsion) * Signal transmission, the process of sending and propagating an analogue or digital information signal ** Analogue transmission - the process of sending and propagating an analogue signal ** Data transmission, the process of sending and propagating digital information ** Signaling (telecommunications) - transmission of meta-information related to the actual transmission * Monetary transmission mechanism, process by which asset prices and general economic conditions are affected as a result of monetary policy decisions * Pathogen transmission, the passing of a disease from an infected host individual or group to a particular individual or group * Cellular signaling - transmission of signals within or bet ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fax Machine
Fax (short for facsimile), sometimes called telecopying or telefax (the latter short for telefacsimile), is the telephonic transmission of scanned printed material (both text and images), normally to a telephone number connected to a printer or other output device. The original document is scanned with a fax machine (or a telecopier), which processes the contents (text or images) as a single fixed graphic image, converting it into a bitmap, and then transmitting it through the telephone system in the form of audio-frequency tones. The receiving fax machine interprets the tones and reconstructs the image, printing a paper copy. Early systems used direct conversions of image darkness to audio tone in a continuous or analog manner. Since the 1980s, most machines modulate the transmitted audio frequencies using a digital representation of the page which is compressed to quickly transmit areas which are all-white or all-black. Fax machines were ubiquitous in office environments in t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fax Modem
A fax modem enables a computer to transmit and receive documents as faxes on a telephone line. A fax modem is like a data modem but is designed to transmit and receive documents to and from a fax machine or another fax modem. Some, but not all, fax modems do double duty as data modems. As with other modems, fax modems can be internal or external. Internal fax modems are often called fax boards. In the early 1990s small business PCs commonly had a PC-based fax/modem card and fax software (typically WinFax Pro). Largely replaced by email, PC-based faxing with a fax/modem declined at the turn of the century. Where faxing from a PC is required there are a number of Internet-based faxing alternatives. Where businesses still had one or more traditional fax machines churning out pages, they were usually outnumbered by PCs processing E-mail. PC faxing Computer users may set up a PC fax/modem with card, telephone line access and software. A special printer driver may be included to all ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Transmission Error
Transmission may refer to: Medicine, science and technology * Power transmission ** Electric power transmission ** Propulsion transmission, technology allowing controlled application of power *** Automatic transmission *** Manual transmission *** Electric transmission (propulsion) * Signal transmission, the process of sending and propagating an analogue or digital information signal ** Analogue transmission - the process of sending and propagating an analogue signal ** Data transmission, the process of sending and propagating digital information ** Signaling (telecommunications) - transmission of meta-information related to the actual transmission * Monetary transmission mechanism, process by which asset prices and general economic conditions are affected as a result of monetary policy decisions * Pathogen transmission, the passing of a disease from an infected host individual or group to a particular individual or group * Cellular signaling - transmission of signals within or bet ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Telephone Line
A telephone line or telephone circuit (or just line or circuit industrywide) is a single-user circuit on a telephone communication system. It is designed to reproduce speech of a quality that is understandable. It is the physical wire or other signaling medium connecting the user's telephone apparatus to the telecommunications network, and usually also implies a single telephone number for billing purposes reserved for that user. Telephone lines are used to deliver landline telephone service and Digital subscriber line (DSL) phone cable service to the premises. Telephone overhead lines are connected to the public switched telephone network. The voltage at a subscriber's network interface is typically 48 V between the ring and tip wires, with tip near ground and ring at -48 V. In the United States In 1878, the Bell Telephone Company began to use two-wire circuits, called the local loop, from each user's telephone to end offices which performed any necessary electrical s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Noise
Noise is unwanted sound considered unpleasant, loud or disruptive to hearing. From a physics standpoint, there is no distinction between noise and desired sound, as both are vibrations through a medium, such as air or water. The difference arises when the brain receives and perceives a sound. Acoustic noise is any sound in the acoustic domain, either deliberate (e.g., music or speech) or unintended. In contrast, Noise (electronics), noise in electronics may not be audible to the human ear and may require instruments for detection. In audio engineering, noise can refer to the unwanted residual electronic noise signal that gives rise to acoustic noise heard as a Hiss (electromagnetic), hiss. This signal noise is commonly measured using A-weighting or ITU-R 468 noise weighting, ITU-R 468 weighting. In experimental sciences, noise can refer to any random fluctuations of data that hinders perception of a signal. Measurement Sound is measured based on the amplitude and frequency ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Block (telecommunications)
In telecommunications a block is one of: * A group of bits or digits that is transmitted as a unit and that may be encoded for error-control purposes. * A string of records, words, or characters, that for technical or logical purposes are treated as a unit. Blocks (a) are separated by interblock gaps, (b) are delimited by an end-of-block signal, and (c) may contain one or more records. A block is usually subjected to some type of block processing, such as multidimensional parity checking, associated with it. A block transfer attempt is a coordinated sequence of user and telecommunication system activities undertaken to effect transfer of an individual block from a source user to a destination user. A block transfer attempt begins when the first bit of the block crosses the functional interface between the source user and the telecommunication system. A block transfer attempt ends either in ''successful block transfer'' or in ''block transfer failure''. Successful block transfe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Receiver (information Theory)
The receiver in information theory is the receiving end of a communication channel. It receives decoded messages/information from the sender, who first encoded them. Sometimes the receiver is modeled so as to include the decoder. Real-world receivers like radio receivers or telephones can not be expected to receive as much information as predicted by the noisy channel coding theorem In information theory, the noisy-channel coding theorem (sometimes Shannon's theorem or Shannon's limit), establishes that for any given degree of noise contamination of a communication channel, it is possible to communicate discrete data (di .... References {{Authority control Information theory ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Check-sum
A checksum is a small-sized block of data derived from another block of digital data for the purpose of detecting errors that may have been introduced during its transmission or storage. By themselves, checksums are often used to verify data integrity but are not relied upon to verify data authenticity. The procedure which generates this checksum is called a checksum function or checksum algorithm. Depending on its design goals, a good checksum algorithm usually outputs a significantly different value, even for small changes made to the input. This is especially true of cryptographic hash functions, which may be used to detect many data corruption errors and verify overall data integrity; if the computed checksum for the current data input matches the stored value of a previously computed checksum, there is a very high probability the data has not been accidentally altered or corrupted. Checksum functions are related to hash functions, fingerprints, randomization functions, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
