Two-way Satellite-only Communication
Two-way satellite Internet service involves both sending and receiving data from a remote very-small-aperture terminal (VSAT) via satellite to a hub telecommunications port (teleport), which then relays data via the terrestrial Internet. The satellite dish at each location must be precisely pointed to avoid interference with other satellites. The two way satellite market can be divided into those systems that support professional applications, such as banking, retail etc. and those built to provide home or small business users with access. The key difference between these systems can be seen in their ability to support advanced quality of service controls. While systems for professionals such as those from iDirect will allow the operator to define and meet strict service level agreements - those used for consumer access provide a 'best effort' service level.
Some providers oblige the customer to pay for a member of the provider's staff to install the system and correctly align the dish—although the European ASTRA2Connect system encourages user-installation and provides detailed instructions for this. Many customers in the Middle East and Africa are also encouraged to do self installs. At each VSAT site the uplink frequency, bit rate and power must be accurately set, under control of the service provider hub.
There are several types of two way satellite Internet services, including time division multiple access (TDMA) and single channel per carrier (SCPC). Two-way systems can be simple VSAT terminals with a 60–100 cm dish and output power of only a few watts intended for consumers and small business or larger systems which provide more bandwidth. Such systems are frequently marketed as "satellite broadband" and can cost two to three times as much per month as land-based systems such as ADSL. The modems required for this service are often proprietary, but some are compatible with several different providers. They are also expensive, costing in the range of US$600 to $2000.
The two-way "iLNB" used on the ASTRA2Connect terminal dish has a transmitter and single-polarity receive LNB, both operating in the Ku band. Pricing for Astra2Connect modems range from €299 to €350. These types of system are generally unsuitable for use on moving vehicles, although some dishes may be fitted to an automatic pan and tilt mechanism to continuously re-align the dish—but these are more expensive. The technology for ASTRA2Connect was delivered by a Belgian company called Newtec.
Read more about this topic: Satellite Internet
Famous quotes containing the word two-way:
“Think of the child’s question as the start of a two-way conversation rather than a question-and-answer session. Sometimes it may be necessary to learn what children think about the subject and what misconceptions they may have before providing an answer.”
—Ruth Formanek (20th century)