Adsl, full name asymmetric digital subscriber line (asymmetric digital subscriber line) is a new mode of data transmission. Adsl's upper and lower bandwidth is asymmetrical and therefore referred to asymmetric digital subscriber lines。
Adsl uses frequency-sharing techniques to divide ordinary telephone lines into three relatively independent channels, telephone, upper and lower, avoiding interference. Adsl is able to make full use of existing telephone lines without rewiring and directly using existing telephone lines, with only the installation of adsl equipment at both ends of the line, thus significantly reducing the cost of services. Generally, the adsl rate depends on the distance of the line, the longer the line, the lower the rate. However, due to technical constraints, the adsl supported a maximum up speed of 1 mbps, a maximum down speed of 8 mbps and an effective transmission distance of 3 to 5 km. Since adsl can be installed with a cat directly on the telephone line, it is extremely convenient to have access to the broadband in the home for many years. Users use adsl terminals, commonly called cats。
Here's a common adsl broadband cat。
In practice, in order to reduce interference between telephone and network signals, the general cat is preceded by a separators, as shown in the figure below。
The separators and cats are combined, as shown below。
There are also two types of adsl broadband cat work model: the route mode, the adsl broadband cat dial-up, and the line-connected computer directly online; and the bridge mode, which requires the establishment of a broadband dial-up and access via the pppe dial-up。
Pppe is a network protocol, full name point to point protocol over ethernet. Computers that access the internet through adsl are connected to the internet via webcards using common tcp/ip methods. The dial-up is available on the internet using the pppe protocol, which applies in particular to adsl, etc。
With advances in technology, demand for network bandwidth has increased, with downband bandwidth of up to 8m not meeting people's needs, broadband in sub-regions, and cable subscribers replacing adsl access。
