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Superframe
In telecommunications, superframe (SF) is a T1 framing standard. In the 1970s it replaced the original T1/D1 framing scheme of the 1960s in which the framing bit simply alternated between 0 and 1. Superframe is sometimes called D4 Framing to avoid confusion with single-frequency signaling. It was first supported by the D2 channel bank, but it was first widely deployed with the D4 channel bank. In order to determine where each channel is located in the stream of data being received, each set of 24 channels is aligned in a frame. The frame is 192 bits long (8 * 24), and is terminated with a 193rd bit, the framing bit, which is used to find the end of the frame. In order for the framing bit to be located by receiving equipment, a predictable pattern is sent on this bit. Equipment will search for a bit which has the correct pattern, and will align its framing based on that bit. The pattern sent is 12 bits long, so every group of 12 frames is called a superframe. The pattern u ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
T-carrier
The T-carrier is a member of the series of carrier systems developed by AT&T Bell Laboratories for digital transmission of multiplexed telephone calls. The first version, the Transmission System 1 (T1), was introduced in 1962 in the Bell System, and could transmit up to 24 telephone calls simultaneously over a single transmission line of copper wire. Subsequent specifications carried multiples of the basic T1 (1.544 Mbit/s) data rates, such as T2 (6.312 Mbit/s) with 96 channels, T3 (44.736 Mbit/s) with 672 channels, and others. Although a ''T2'' was defined as part of AT&T's T-carrier system, which defined five levels, T1 through T5, only the T1 and T3 were commonly in use.1999 ad: On the left, in an aisle seat, a man who very much "filled" his airline seat while on the right side of the aisle is a height-challenged man whose shoe toes barely reach the floor Transmission System 1 The T-carrier is a hardware specification for carrying multiple time-division mul ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Extended Superframe
In telecommunications, superframe (SF) is a T1 framing standard. In the 1970s it replaced the original T1/D1 framing scheme of the 1960s in which the framing bit simply alternated between 0 and 1. Superframe is sometimes called D4 Framing to avoid confusion with single-frequency signaling. It was first supported by the D2 channel bank, but it was first widely deployed with the D4 channel bank. In order to determine where each channel is located in the stream of data being received, each set of 24 channels is aligned in a frame. The frame is 192 bits long (8 * 24), and is terminated with a 193rd bit, the framing bit, which is used to find the end of the frame. In order for the framing bit to be located by receiving equipment, a predictable pattern is sent on this bit. Equipment will search for a bit which has the correct pattern, and will align its framing based on that bit. The pattern sent is 12 bits long, so every group of 12 frames is called a superframe. The pattern ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Frame Synchronization
In telecommunication, frame synchronization or framing is the process by which, while receiving a stream of framed data, incoming frame alignment signals (i.e., a distinctive bit sequences or syncwords) are identified (that is, distinguished from data bits), permitting the data bits within the frame to be extracted for decoding or retransmission. Framing If the transmission is temporarily interrupted, or a bit slip event occurs, the receiver must re-synchronize. The transmitter and the receiver must agree ahead of time on which frame synchronization scheme they will use. Common frame synchronization schemes are: ;Framing bit: A common practice in telecommunications, for example in T-carrier, is to insert, in a dedicated time slot within the frame, a noninformation bit or framing bit that is used for synchronization of the incoming data with the receiver. In a bit stream, framing bits indicate the beginning or end of a frame. They occur at specified positions in the frame, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Frame Synchronization
In telecommunication, frame synchronization or framing is the process by which, while receiving a stream of framed data, incoming frame alignment signals (i.e., a distinctive bit sequences or syncwords) are identified (that is, distinguished from data bits), permitting the data bits within the frame to be extracted for decoding or retransmission. Framing If the transmission is temporarily interrupted, or a bit slip event occurs, the receiver must re-synchronize. The transmitter and the receiver must agree ahead of time on which frame synchronization scheme they will use. Common frame synchronization schemes are: ;Framing bit: A common practice in telecommunications, for example in T-carrier, is to insert, in a dedicated time slot within the frame, a noninformation bit or framing bit that is used for synchronization of the incoming data with the receiver. In a bit stream, framing bits indicate the beginning or end of a frame. They occur at specified positions in the frame, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Telecommunication
Telecommunication is the transmission of information by various types of technologies over wire, radio, optical, or other electromagnetic systems. It has its origin in the desire of humans for communication over a distance greater than that feasible with the human voice, but with a similar scale of expediency; thus, slow systems (such as postal mail) are excluded from the field. The transmission media in telecommunication have evolved through numerous stages of technology, from beacons and other visual signals (such as smoke signals, semaphore telegraphs, signal flags, and optical heliographs), to electrical cable and electromagnetic radiation, including light. Such transmission paths are often divided into communication channels, which afford the advantages of multiplexing multiple concurrent communication sessions. ''Telecommunication'' is often used in its plural form. Other examples of pre-modern long-distance communication included audio messages, such as coded drumb ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Out-of-band Data
In computer networking, out-of-band data is the data transferred through a stream that is independent from the main ''in-band'' data stream. An out-of-band data mechanism provides a conceptually independent channel, which allows any data sent via that mechanism to be kept separate from in-band data. The out-of-band data mechanism should be provided as an inherent characteristic of the data channel and transmission protocol, rather than requiring a separate channel and endpoints to be established. The term "out-of-band data" probably derives from out-of-band signaling, as used in the telecommunications industry. Example case Consider a networking application that tunnels data from a remote data source to a remote destination. The data being tunneled may consist of any bit patterns. The sending end of the tunnel may at times have conditions that it needs to notify the receiving end about. However, it cannot simply insert a message to the receiving end because that end will not be a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Multiplexing
In telecommunications and computer networking, multiplexing (sometimes contracted to muxing) is a method by which multiple analog or digital signals are combined into one signal over a shared medium. The aim is to share a scarce resource - a physical transmission medium. For example, in telecommunications, several telephone calls may be carried using one wire. Multiplexing originated in telegraphy in the 1870s, and is now widely applied in communications. In telephony, George Owen Squier is credited with the development of telephone carrier multiplexing in 1910. The multiplexed signal is transmitted over a communication channel such as a cable. The multiplexing divides the capacity of the communication channel into several logical channels, one for each message signal or data stream to be transferred. A reverse process, known as demultiplexing, extracts the original channels on the receiver end. A device that performs the multiplexing is called a multiplexer (MUX), and a dev ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cyclic Redundancy Check
A cyclic redundancy check (CRC) is an error-detecting code commonly used in digital networks and storage devices to detect accidental changes to digital data. Blocks of data entering these systems get a short ''check value'' attached, based on the remainder of a polynomial division of their contents. On retrieval, the calculation is repeated and, in the event the check values do not match, corrective action can be taken against data corruption. CRCs can be used for error correction (see bitfilters). CRCs are so called because the ''check'' (data verification) value is a ''redundancy'' (it expands the message without adding information) and the algorithm is based on ''cyclic'' codes. CRCs are popular because they are simple to implement in binary hardware, easy to analyze mathematically, and particularly good at detecting common errors caused by noise in transmission channels. Because the check value has a fixed length, the function that generates it is occasionally used as a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Data Frame
A frame is a digital data transmission unit in computer networking and telecommunication. In packet switched systems, a frame is a simple container for a single network packet. In other telecommunications systems, a frame is a repeating structure supporting time-division multiplexing. A frame typically includes frame synchronization features consisting of a sequence of bits or symbols that indicate to the receiver the beginning and end of the payload data within the stream of symbols or bits it receives. If a receiver is connected to the system during frame transmission, it ignores the data until it detects a new frame synchronization sequence. Packet switching In the OSI model of computer networking, a frame is the protocol data unit at the data link layer. Frames are the result of the final layer of encapsulation before the data is transmitted over the physical layer. A frame is "the unit of transmission in a link layer protocol, and consists of a link layer header followed by ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Telecommunication Circuit
A telecommunication circuit is a path in a telecommunications network used to transmit information. Circuits have evolved over time from generally being built on physical connections between individual hardware cables, as in an analog phone switch, to virtual circuits established over packet switching networks. Definitions A telecommunication circuit may be defined as follows: * The complete path between two terminals over which one-way or two-way communications may be provided. * An electronic path between two or more points, capable of providing a single or multiple communication channels. * An electronic closed-loop path among two or more points used for signal transfer. In operational terms, a telecommunication circuit may be capable of transmitting information in only one direction (''simplex'' circuit), or it may be bi-directional (''duplex'' circuit). Bi-directional circuits may support half- duplex operation, when only one end of the channel transmits at any one time, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Monitoring
Monitoring may refer to: Science and technology Biology and healthcare * Monitoring (medicine), the observation of a disease, condition or one or several medical parameters over time * Baby monitoring * Biomonitoring, of toxic chemical compounds, elements, or their metabolites, in biological substances * Fetal monitoring in childbirth * Heart rate monitoring * Intraoperative neurophysiological monitoring * Monitoring in clinical trials, oversight and administrative efforts that monitor a participant's health during a clinical trial * Self-monitoring, a psychological term meaning awareness of what one knows Computing * Application performance management, also called application performance monitoring, monitoring and management of performance and availability of software applications * Event monitoring, process of collecting, analyzing, and signaling event occurrences to subscribers such as operating system processes, active database rules as well as human operators * Business trans ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Synchronization
Synchronization is the coordination of events to operate a system in unison. For example, the conductor of an orchestra keeps the orchestra synchronized or ''in time''. Systems that operate with all parts in synchrony are said to be synchronous or ''in sync''—and those that are not are '' asynchronous''. Today, time synchronization can occur between systems around the world through satellite navigation signals and other time and frequency transfer techniques. Navigation and railways Time-keeping and synchronization of clocks is a critical problem in long-distance ocean navigation. Before radio navigation and satellite-based navigation, navigators required accurate time in conjunction with astronomical observations to determine how far east or west their vessel traveled. The invention of an accurate marine chronometer revolutionized marine navigation. By the end of the 19th century, important ports provided time signals in the form of a signal gun, flag, or dropping time ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
