High-speed access for multimedia services

Asymmetric Digital subscriber Line (ADSL) technology can quickly and efficiently transfer the rich content of multimedia applications to end users. -sasktel, a leading company in Saskatchewan, Prov. Communications in Canada, uses its existing copper-wire access network to provide ADSL as a transitional way to provide Internet access. This will be maintained to the commercial and regulatory environment into a carefully shifted fiber-dominated infrastructure phase. The new business has long been shown to Asian delegations, including representatives of Japan's NTT and Telie-phil Inc., a consortium of Philippine telecom suppliers.

In the 1996, SaskTel Company opened "Sympaticohigh-speed", the first commercial high-speed Internet access using ADSL technology in the world. The system also provides a 1.54MBIT/S data channel, a 64kbit/s high data channel and a standard telephone channel. Fast dirty connections are 50 times times faster than standard 28.8kbit/s modems, which can download large text, graphics, video, and audio files on the Internet. This means that the 2.5-hour download is usually 10 MB than the video information, on the sympaticohigh-speed only need 45 seconds.

Configure ADSL Service

In the implementation of SaskTel company, an ADSL terminal unit is added to the main cable distribution frame of the local telephone switch, so that the ADSL signal is plugged into the user's existing telephone line. From the wiring frame switch side of the user to the ADSL unit to set a jumper, another jumper from the ADSL unit back to the distribution line side of the line between the user, this configuration so that the telephone line through the local switch ADSL equipment bypass.

In a local switch, each subscriber line has a modem (called a atu-c) that will connect the high-speed Ethernet (Ethernet) signal from the primary Internet business into the cable pair and the regular phone signal. The combination of the signal through the wiring frame through the cable to the user home of another modem (ATU-R). Atu-r the telephone signal and turns the ADSL number back to the Ethernet signal to connect to the user's computer.

Push the high-speed Internet to the market

The first generation of SaskTel's high-speed business was limited to about 130,000 households, and was located within a 4 km radius of the two largest cities in Saskatchewan, Prov., Saskatoon (Saskatoon) and Regina (Regina). Second-generation businesses can expand their business to other central towns in the province when technology and demand verification are needed to expand. Initial business charges are 72 USD installation fee and 50 USD monthly charge. At this price, the user gets a one-year unlimited access, a set of "Sympatico" software (including custom netscapenavigator browsing tools), an ADSL (ATU-R) modem, an e-mail account and 2 MB of personal web space, All of the above items are in the first door-to-door service fashion at the user's residence. Each user can also receive a personal service from the supplier because the supplier can access the 24-hour help desk.

Sympaticohigh-speed works on very common computers, such as a 486dx66 processor, 6 megabytes of free disk space, 8 megabytes of RAM, and Windows3.1, windowsforworkgroups, or windows\ ' 95 PC of the operating platform.

The goal of the market is to 85-90% Internet users in two cities in the service area. More typically, these users use bandwidth-intensive content (graphics, animation, interactive gaming, transaction processing) and therefore benefit from high transmission rates. Information providers are not considered in the first application because of concerns about security issues and possible conflicts with other businesses of the SaskTel company (for example, ISDN).

SaskTel mainly through the service area of good reputation of the operators to promote and sell high-speed business. The main advantages of making users believe that the Sympaticohigh-speed business is connected:

Speed and convenience

Better access to multimedia applications and content

Unrestricted use

No second line because the phone and the Internet work on one line at a time

The business does not need to dial, so it has been opened

Users do not have to worry about hardware rents, because SaskTel has an ADSL modem in the user's home.

Technical issues

One of the technical problems is how to send the reusable ADSL signal and the ordinary telephone signal on the same copper wire, without causing the business to reduce the quality. Standard telephone frequency in the frequency band up to 4KHz, and most ADSL signal range of up to 20KHz up to 200-1000khz, depending on the implementation of ADSL standards. At the user's residence, a filter is required to prevent high-frequency ADSL signals from being audible to the phone. On the other hand, picking a low-frequency telephone signal without a filter can damage the ADSL performance. The problem is where to set the filter. SaskTel's first filter used in its intermediate tests had to be placed in the user's home atu-r modem. Although it works well, the SaskTel has decided to use an external filter when it operates because it has greater flexibility in installation. Security is often a matter of concern when using a network. Sympaticohigh-speed is actually a local area network (LAN).

The user system is connected to the LAN. However, users should still be responsible for taking appropriate measures to ensure that users are not negligent in opening their documents to unauthorized access. All operating system default conventions that are compatible with sympaticohigh-speed are the safest option, so unless users take specific steps to change these settings and share files, the Internet business provided on ADSL should be as secure as it is.

Given that the SaskTel does not yet have a suitable system for measuring the timing of users, the first generation of Sympaticohigh-speed provided to residents is only a flat rate. Business users are more likely to send large files in both directions (high and low), and they are also allowed to develop a billing system that contains parts for consumption. From a technical point of view, all that is required is a system that handles the information collected by existing modems on a local switch and accounts accordingly.

From a long-term perspective, standardization may be the most important technical issue. As the cost of modems declines steadily, the technical standards of the system continue to improve. The problem of providing communication companies based on ADSL business is to deal with technological progress in a way that saves costs and responds to the needs of users.