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Digital Signal Designation
Digital Signal Designation is the classification of digital bit rates in the digital multiplex hierarchy used in transport of signals from one location to another in telecommunications. The DS technically refers to the rate and format of the signal, while the T designation refers to the equipment providing the signals. In practice, "DS" and "T" are used synonymously; for example, DS1 and T1, DS3 and T3. Digital signal line rates North America Europe Optical carrier See SONET Synchronous optical networking (SONET) and synchronous digital hierarchy (SDH) are standardized protocols that transfer multiple digital bit streams synchronously over optical fiber using lasers or highly coherent light from light-emitting diode ... for more information. References Multiplexing {{telecomm-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Digital Multiplex Hierarchy
In telecommunications, a digital multiplex hierarchy is a hierarchy consisting of an ordered repetition of tandem digital multiplexers that produce signals of successively higher data rates at each level of the hierarchy. Digital multiplexing hierarchies may be implemented in many different configurations depending on; (a) the number of channels desired, (b) the signaling system to be used, and (c) the bit rate allowed by the communications media. Some currently available digital multiplexers have been designated as Dl-, DS-, or M-series, all of which operate at T-carrier rates. In the design of digital multiplex hierarchies, care must be exercised to ensure interoperability of the multiplexers used in the hierarchy. Digroup Digroup is an abbreviation for digital group. In telephony, a basic group in the digital multiplex hierarchy. In the North American and Japanese T-carrier digital hierarchies, each digroup supports 12 PCM voice channels or their equivalent in other servi ... [...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] |
Digital Signal 1
Digital Signal 1 (DS1, sometimes DS-1) is a T-carrier signaling scheme devised by Bell Labs. DS1 is the primary digital telephone standard used in the United States, Canada and Japan and is able to transmit up to 24 multiplexed voice and data calls over telephone lines. E-carrier is used in place of T-carrier outside the United States, Canada, Japan, and South Korea. DS1 is the logical bit pattern used over a physical T1 line; in practice, the terms ''DS1'' and ''T1'' are often used interchangeably. Overview T1 refers to the primary digital telephone carrier system used in North America. T1 is one line type of the PCM T-carrier hierarchy. T1 describes the cabling, signal type, and signal regeneration requirements of the carrier system. The signal transmitted on a T1 line, referred to as the DS1 signal, consists of serial bits transmitted at the rate of 1.544 Mbit/s. The type of line code used is called Alternate Mark Inversion (AMI). Digital Signal Designation is the classifi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Digital Signal 3
A Digital Signal 3 (DS3) is a digital signal level 3 T-carrier. It may also be referred to as a T3 line. *The data rate for this type of signal is 44.736 Mbit/s (45 Mb). *DS3 uses 75ohm coaxial cable and BNC connectors. *This level of carrier can transport 28 DS1 level signals within its payload. *This level of carrier can transport 672 DS0 level channels within its payload. *Such circuits are the usual kind between telephony carriers, both wired and wireless, and typically by OC1 optical connections. Cabling DS3 interconnect cables must be made with true 75-ohm coaxial cable and connectors. Cables or connectors which are 50 ohms or which significantly deviate from 75 ohms will result in signal reflections which will lower the performance of the connection, possibly to the point of not working. GR-139-CORE ''Generic Requirements for Central Office Coaxial Cable'', defines type 734 and 735 cables for this application. Due to losses, there are differing distance limitations for ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
DS4/NA
The Digital Signal 4/NA (DS4/NA) in telecommunications, is a 139.264-Mbit/s aggregate- multiplexed signal, equivalent to 3 Digital Signal 3s or 2,016 Digital Signal 0s. This link is commonly used for long distance fiber carriage of broadcast radio and television as a platform for the 270Mb/sec MPEG-2/ASI Transport Stream. The circuits are in common use daily for digital transmission of broadcast television and radio, interconnecting Sport Arenas, Convention Centers, Television Stations and Broadcasters. The connections themselves become part of long-haul serial data transmission over fiber. As these are sent as purely serial data, no packetizing or bandwidth sharing takes place as with TCP/IP. Carriers usually supplying these circuits are specialized, most often supplied in the US by Vyvx or The Switch. A remote broadcast, a sports event for example, is typically carried over a DS4 from the venue to the television network on a full, unshared serial data circuit of 270 Megabi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
SONET
Synchronous optical networking (SONET) and synchronous digital hierarchy (SDH) are standardized protocols that transfer multiple digital bit streams synchronously over optical fiber using lasers or highly coherent light from light-emitting diodes (LEDs). At low transmission rates data can also be transferred via an electrical interface. The method was developed to replace the plesiochronous digital hierarchy (PDH) system for transporting large amounts of telephone calls and data traffic over the same fiber without the problems of synchronization. SONET and SDH, which are essentially the same, were originally designed to transport circuit mode communications (e.g., DS1, DS3) from a variety of different sources, but they were primarily designed to support real-time, uncompressed, circuit-switched voice encoded in PCM format. The primary difficulty in doing this prior to SONET/SDH was that the synchronization sources of these various circuits were different. This meant that each ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
