ADSL guide, What is ADSL?

ADSL (Asymmetrical Digital Subscriber Line) is a broadband access service providing a permanent access to the Internet at a higher bit rate than dial-up or ISDN access to the Internet.
The service operates on special telephone networks with copper pairs. In addition to the voice channel (there is one in the ordinary network and two in the ISDN network), a further two channels are reserved by frequency splitting: one for data upload and the other for data download. The two channels are of different bandwidths, i.e. asymmetrical

("asymmetrical" in ADSL refers to this), since data are downloaded more often than uploaded by users. ADSL offers a maximum download rate of 384 kbit/s and a maximum upload rate of 64 kbit/s.

What are the major features of ADSL?
* Both for duration and data traffic, an unlimited and permanent connection to the Internet.
* Unlimited volume of data downloadable.
* A fixed cost, irrespective of the volume of files downloaded and the time actually spent on the Internet.
* Voice and fax communication are parallel on an analogue telephone line - irrespective of surfing on the Internet.
* An extremely high bit rate: download rate of maximum 384 kbit/s and upload rate of maximum 64 kbit/s. The minimum download rate is guaranteed only on sections operated by Matáv.
* Data security is considerably better than for analogue technologies.
* Available in fewer places than ISDN or traditional dial-up Internet.

What are the major benefits of ADSL?
* Swift download rate (upload rate, less important to the users, is lower but still faster than traditional accesses)
Download rates (kbit/s):

Maximum available bandwidths:
o no usage fee
o unlimited volume of data downloadable
o fixed monthly fee
o unlimited use and permanent connection to the Internet
o can be installed on an existing analogue/ISDN2 line
o simultaneous voice and Internet communication provided by the service

What is needed for using ADSL?
An appropriate telephone connection is essential; a splitter and a special DSL modem are also required on the user end. Both devices are installed by the telecommunications service provider ("tapping" the telephone line and connecting the splitter and the DSL modem).
For use on single home computers, an internal network card or an external USB port adapter is needed; they can be purchased separately or together with the modem.
In addition, a special customer software has to run on the computer; such software is a built-in element of recent operating systems (e.g. Windows XP). The software required for earlier operating systems can be downloaded from Axelero's website or can be run using the CD provided for set-up; for Linux, free software can be downloaded from the Internet.

What is the benefit to me if I have a network card or a USB adapter? What is the difference between the two options?
A network card or a USB adapter is essential for making the computer able to provide high-rate data transmission. Traditional modems are connected to the serial port of the computer, but the rate of the serial port is unable to transmit the data traffic of the cable modem. Both the network card and the USB adapter meet the requirements of the ADSL service. If there is no more space for peripherals in the computer case (or e.g. a laptop or possibly several computers are used alternately), a USB adapter is definitely recommended. In all other cases, it is advisable to choose the network card.

When is it worth buying ADSL?
User demands and technical capabilities determine whether it is worth subscribing to a dial-up, Internet, ADSL or CaTV Internet service.
For home users, ADSL service is an excellent choice. A significant benefit of ADSL is that, compared to other broadband accesses, the bottleneck section - i.e. the cable section between the user's premises and the data link node - is only used by one subscriber for Internet access.

ADSL, cable TV, ISDN, Dial up - all provide access to the Internet; what is the difference?

ADSL
ADSL, using special copper pair telephone networks, offers: sending and receiving any combination of high bit-rate and high-quality data, text and video information.
Upload rate (max 64 kbit/s) and download rate (max 384 kbit/s) are different since data are downloaded more often than uploaded by users; as the word "asymmetrical" in the name indicates.
ADSL provides the benefit of a significant capacity due to the broadband access and a permanent connection, as well as an unlimited volume of data downloadable.

Cablenet
Cablenet provides a permanent broadband access to the Internet, with a high-rate information stream, with no telephone line required, over a CaTV network. A drawback is that the CaTV network in general has to be modified to make it able to provide a two-way connection; and, for the time being, it is available in very few places.

ISDN
ISDN offers sending and receiving, over the same connection, any combination of high bit-rate and high-quality voice, data, text and video information, over one or several isochronous connections.
For access to the Internet over an ISDN connection, a special ISDN modem is required. However, this method provides a narrow-band access (maximum download and upload rates of 128 kbit/s) and does not provide a permanent access.

Analogue telephone line - Dial-up access
Dial-up access implemented over a traditional telephone line was the first way to have access to the Internet. However, the telephone network was not originally developed for this purpose, so it does not provide permanent access or an appropriate capacity and, due to the narrow bandwidth, the information stream is not really fast (max. 64 Kbit/s) either.

8. What is the difference between ADSL and ISDN?
The main difference between the two services is that ISDN provides narrow-band access and ADSL provides broadband access to the Internet.

ADSL (Asymmetrical Digital Subscriber Line) operates exclusively on special telephone networks including copper pairs. However, important conditions for the service are as follows:
" the copper network must have an appropriate spare capacity;
" user's premises must not be too far from the exchange; in general the maximum distance is 4.5 km;
" in addition to the distance, other features of the copper wire, such as diameter and loop resistance, also have an impact;
" on the exchange side, splitters need to be installed.
In addition to the voice channel (one in the analogue network and two in the ISDN network), a further two channels are reserved by frequency splitting: one for data upload and the other for data download.
The two channels are of different bandwidths, i.e. asymmetrical ("asymmetrical" in ADSL refers to this), since data are downloaded more often than uploaded by users. ADSL offers a maximum download rate of 384 kbit/s and a maximum upload rate of 64 kbit/s.
Voice and data traffic are unbundled, according to frequency, by a splitter installed at the user's end and at the exchange end. In addition to all this, ADSL provides a permanent and unlimited connection to the Internet.

By digitizing the final section of the network, i.e. the subscriber access, ISDN provides an end-to-end digital transmission. An ISDN modem needs to be installed for this purpose. It provides a relatively broad bandwidth (upload and download rate of max. 128 kbit/s), however, no permanent connection is possible.

9. What are the maximum download and upload rates of the various accesses to the Internet?