What is DSL?
Digital Subscriber Line, or DSL, is a family of technologies, used to provide a digital connection between a home or office user's telephone (and PC) and the local telephone exchange. DSL still uses the same copper cables that ordinary analogue phones use. The different types of DSL connections are mainly differentiated by the bit rate or bandwidth of the connection. ADSL, or Asymmetric DSL, gets its name from the fact that the upstream bandwidth (from the user to the exchange) and downstream bandwidth (from the exchange to the user) are different. Usually, the downstream bandwidth is higher than the upstream bandwidth.
When an ADSL line to a home or office is obtained, it is still possible to connect an analogue telephone on the same phone line, and to use the phone at the same time as a connection to the Internet is established.
ADSL is what is known as an "always on" technology. This means that users do not have to dial a phone call to connect to the Internet. The ADSL line is always connected to the local telephone exchange, and is always available. However, the telephone company (Telkom) and/or the Internet Service Provider (FirstNet) may, logically disconnect any session after a defined time of inactivity has passed, forcing users to login periodically. Unlike dial-up connections, however, users do not pay based on the amount of time that they are connected -- the monthly line rental provides for continuous availability of access.

What hardware is needed to connect via ADSL?
The main piece of equipment that is required to connect an ADSL line to a PC is an ICASA-approved ADSL modem. These come in two main varieties, using either a USB or Ethernet connection to connect to your computer. Most modern PCs have USB ports, thus making it easy to connect a USB ADSL modem. If you opt for an Ethernet ADSL modem, your PC will require an Ethernet card, in addition to the correct type of Ethernet cable to connect the PC to the ADSL modem. Typically, USB modems are cheaper than Ethernet modems. The exact operating system and hardware requirements will depend on the modem selected and driver availability.
It is important to note that other factors like network availability, line length, copper quality and therefore the line sync speed will determine whether or not Telkom can provide ADSL access at a specific location. Telkom therefore advises that no PC upgrades be performed prior to obtaining confirmation that the ADSL access service can be provided.

How is an ADSL line obtained?
In order to obtain ADSL connectivity, two separate components are required, namely:
• An ADSL phone line, which can only be obtained from Telkom and
• An ADSL Internet access package, which can be obtained from an ISP such as one of Internet Solutions Virtual ISPs or Value Added Partner.
ADSL lines are not available in all Telkom local exchanges. In order to confirm whether or not your local Telkom Exchange is ADSL enabled, please visit http://www.telkom.co.za. Telkom can provide ADSL access at the local exchange. An ADSL line can then be ordered by phoning Telkom on 0800 DSL DSL.

What does an ADSL line cost?
To obtain an ADSL line from Telkom, the following costs will be incurred:
• Telkom's normal phone line rental
• The normal charges of all your voice phone calls (billed by Telkom)
• Telkom's once-off installation charge.
• The monthly rental of an ADSL line from Telkom.
• An ADSL Ethernet or USB modem, which can be purchased either from Telkom, or another supplier.
The Internet access portion for ADSL access is charged separately from the Telkom charges for your ADSL line. This fee is payable to First Technology and is dependant on the DSL package purchased.

What is the difference between ADSL, ISDN and Diginet or leased line services?

ADSL
ADSL (Asymmetric Digital Subscriber Line) is an access medium that provides the user with a broadband connection to Telkom's data network. The first service offered over ADSL is an always-available connection to the Internet. In the future Telkom will provide more value-add services over ADSL. Telkom does not guarantee any throughput speeds on an ADSL access line.
ADSL operates over the same pair of copper wires that is used for telephone service, and is provided only in conjunction with a telephone service. You can make and receive calls or send a fax and surf the Internet at the same time. Telkom's ADSL access service will offer you an always-available connection with no dial-up necessary, no more waiting to establish a connection and no more busy signals. You will not be billed for your connection time when you make use of Telkom's ADSL access service.

ISDN
ISDN (Integrated Services Digital Network) is a switched dial-up connection that enables the user to dial-up to any destination number within the network. A user can therefore access the Internet or a videoconference. Telkom does not guarantee any throughput speeds if a user accesses the Internet utilizing an ISDN line.
The customer will be billed for their connection time when making use of Telkom's ISDN service to surf the Internet.

Diginet / leased line services
Diginet or leased line services are dedicated point-to-point connections providing the user with an always on service. Diginet is based on carrier class Symmetrical Digital Subscriber Line technology that provides guaranteed bandwidths between any predefined destinations. The customer determines the transmission speed "throughput" of the Diginet services as they chose the appropriate speed with application. There is no traffic congestion due to other users as it is used in a private network topology. This also means that customers do not share bandwidth. As Diginet is a constant bit-rate service it means that there is no slowdown of data transmission speed.

Although Telkom guarantees the Diginet throughput speed it does not guarantee any throughput speeds of the Internet. When a user accesses the Internet utilizing a Diginet line the guaranteed throughput stops once the data enters the Internet.

How can I use an ordinary analogue phone line?
As part of the ADSL installation, Telkom install what is known as a POTS splitter. The POTS splitter connects to the ADSL line where it comes from the wall socket, and then has two separate ports, one for the analogue telephone, and one for the ADSL modem.

How can I tell whether ADSL will be available in my home/office?
ADSL is not available in all areas. Before applying for an ADSL line, it is necessary to determine whether Telkom is able to provide ADSL in your area. There are also distance limitations on the service, which restrict availability to an area within approximately 4km of the local telephone exchange. In order to confirm whether or not your local Telkom telephone exchange is ADSL enabled, please have a look at http://www.telkom.co.za or contact them on 0800 DSL DSL.