Deutsche Telekom AG (abbreviated DT, English: German Telecom) is a German telecommunications company headquartered in Bonn. Deutsche Telekom was formed in 1996 as the former state-owned monopoly Deutsche Bundespost was privatized. As of June 2008, the German government still holds a 15% stake in company stock directly, and another 17% through the government bank KfW. The company is a component of the Euro Stoxx 50 stock market index.
The Deutsche Bundespost was the federal German government post office created in 1947 as a successor to the Reichspost. On 1 July 1989, as part of a post office reform, Deutsche Bundespost was split into three entities, one being Deutsche Telekom. On 1 January 1995, as part of another reform, Deutsche Bundespost Telekom became Deutsche Telekom AG, and was privatized in 1996. As such, it shares a common heritage with the other privatized Deutsche Bundespost companies, Deutsche Post (DHL) and Deutsche Postbank.
Deutsche Telekom was the monopoly Internet service provider (ISP) for the German Internet until its privatization in 1995, and the dominant ISP thereafter. Until the early 21st century, Deutsche Telekom controlled almost all Internet access by individuals and small businesses in Germany, as they were one of the first German telekom units.
Telkom-3 is an Indonesian communications satellite which was lost due to a launch failure on 6 August 2012. It was built by ISS Reshetnev for Indonesian telecommunications provider PT Telekomunikasi Indonesia. It was based on the Ekspress-1000 bus and had 32 C band transponders and 16 Ku band transponders. It was due to be located in geosynchronous orbit at 118° east above the equator.
Telkom-3 was launched along with Ekspress MD2 by a Proton-M rocket with Briz-M upper stage on 6 August 2012 at 19:31 UTC. The satellites were launched from Site 81/24 at Baikonur Cosmodrome in Kazakhstan. The first three stages of the Proton launched worked as expected and the satellites were attached to the Briz-M upper stage which would transfer them into geosynchronous orbit. The Briz-M undertakes a series of four burns with coasting stages in order to do this. The third burn was due to be 18 minutes long but the engines cut out after 7 seconds, leaving the satellites in unusable orbits.
Telkom-3 manufacturer ISS Reshetnev announced that the satellite was under control with its solar panels extended but would not be able to be used for its intended purpose as it is in the wrong orbit.
Asymmetric digital subscriber line (ADSL) is a type of digital subscriber line (DSL) technology, a data communications technology that enables faster data transmission over copper telephone lines rather than a conventional voiceband modem can provide. ADSL differs from the less common symmetric digital subscriber line (SDSL). Bandwidth (and bit rate) is greater toward the customer premises (known as downstream) than the reverse (known as upstream). This is why it is called asymmetric. Providers usually market ADSL as a service for consumers to receive Internet access in a relatively passive mode: able to use the higher speed direction for the download from the Internet but not needing to run servers that would require high speed in the other direction.
ADSL works by utilizing frequencies that are not used by a voice telephone call. A splitter, or DSL filter, allows a single telephone connection to be used for both ADSL service and voice calls at the same time. ADSL can generally only be distributed over short distances from the telephone exchange (the last mile), typically less than 4 kilometres (2 mi), but has been known to exceed 8 kilometres (5 mi) if the originally laid wire gauge allows for further distribution.
Adenylosuccinate lyase (or adenylosuccinase) is an enzyme that in humans is encoded by the ADSL gene.
Adenylosuccinate lyase converts adenylosuccinate to AMP and fumarate as part of the purine nucleotide cycle. ASL catalyzes two reactions in the purine biosynthetic pathway that makes AMP; ASL cleaves adenylosuccinate into AMP and fumarate, and cleaves SAICAR into AICAR and fumarate.
Adenylosuccinate lyase is part of the β-elimination superfamily of enzymes and it proceeds through an E1cb reaction mechanism. The enzyme is a homotetramer with three domains in each monomer and four active sites per homotetramer.
Point mutations in adenylosuccinate that cause lowered enzymatic activity cause clinical symptoms that mark the condition adenylosuccinate lyase deficiency.
This protein may use the morpheein model of allosteric regulation.
Adenylosuccinate lyase (ASL) is an enzyme that catalyzes two reactions in the de novo purine biosynthetic pathway. In both reactions it uses an E1cb elimination reaction mechanism to cleave fumarate off of the substrate. In the first reaction, ASL converts 5-aminoimidazole- (N-succinylocarboxamide) ribotide (SAICAR) to 5-aminoimidazole-4-carboxamide ribotide (AICAR) and fumarate. AICAR proceeds through three more reactions before it becomes adenylosuccinate (also called succinyladenosine monophosphate or SAMP), which ASL then splits into adenosine monophosphate (AMP) and fumarate. ASL is important to cells not only because of its involvement in creating purines needed for cellular replication, but also because it helps regulate metabolic processes by controlling the levels of AMP and fumarate in the cell.
ITU G.992.3 is an ITU (International Telecommunication Union) standard, also referred to as ADSL2 or G.dmt.bis. It optionally extends the capability of basic ADSL in data rates to 12 Mbit/s downstream and, depending on Annex version, up to 3.5 Mbit/s upstream (with a mandatory capability of ADSL2 transceivers of 8 Mbit/s downstream and 800 kbit/s upstream). ADSL2 uses the same bandwidth as ADSL but achieves higher throughput via improved modulation techniques. Actual speeds may reduce depending on line quality; usually the most significant factor in line quality is the distance from the DSLAM to the customer's equipment.
ADSL2 has multiple modes for DSL providers to offer services for different needs. Below is a list of available features based on ADSL2 specs from the ITU standards.