ADSL Glossary

Asymmetric Digital Subscriber Line

This is a form of ADSL offering faster speeds of data transfer (not available in South Africa yet)

Asynchronous Transfer Mode
(ATM) – A high-bandwidth, low-delay, standard for digital backbone networks

A network that carries traffic between network end points

Bandwidth is the “width” of a channel used for communication. The term bandwidth can refer to analogue – the range of frequencies used to transmit a signal or digital – the rate of data transmitted in bits per second. Bandwidth is used to describe the amount of data which can be transmitted over a given period of time

The smallest unit of information in a binary number system. A bit can be a “0”, or a “1”. Four bits together for a single character is called a nibble. 8 bits together is called a byte. 16 bits together is known as a word

Bits per second (bps)
The speed at which bits (digital electronic signals) are transmitted. The bps rate may be equal to or greater than the baud rate

A device that connects two networks into a single network using the same networking protocol, such as TCP/IP

Broadband is a generic term for an affordable method of connecting to the Internet using DSL technology, typically ADSL

A browser is an application used to view Internet pages, such as Mozilla Firefox, Microsoft Internet Explorer and Opera

A group of 8 bits which represent one data character

CMD (Command)
This is used in the run box. A DOS prompt box is opened allowing commands to be run, such as ping and ipconfig. This is particularly useful when troubleshooting network difficulties

The most common meaning of “Cookie” on the Internet refers to a piece of information sent by a Web Server to a Web Browser that the Browser software is expected to save and to send back to the Server whenever the browser makes additional requests from the Server

Data Protocols
Describe rules and conventions that determine how devices on a network exchange information

DHCP (Dynamic Host Configuration Protocol)
A protocol that allows remote clients to request configuration information, such as IP host addresses from a server

Refers to data connectivity using the Public Switched Telephone Network (PSTN)

Part of an Internet naming hierarchy. An Internet domain name consists of a sequence of names (labels) separated by periods; for example “”

DNS (Domain Name Service)
DNS is a distributed database used by TCP/IP applications to map between hostnames and IP addresses

DSL Digital Subscriber Line
The generic term that refers to the entire family of DSL technologies, such as SDSL, ISDL, and ADSL. Subscriber line refers to the client (subscriber) local phone line

DSLAM (Digital Subscriber Line Access Multiplexer)
DSLAM is the description for the equipment that is installed in the Telkom exchange that houses the Port cards assigned to every DSL subscriber

Dynamic IP address
Originally all Internet Protocol addresses were static, but with the growth of the internet it soon became clear there wouldn”t be enough to go around. A dynamic IP address changes every time you connect to the internet. Your ISP will have a range of dynamic IP addresses available and you will be allocated any one of these at any time

Ethernet A type of local area network (LAN)
Ethernet was originally designed for data transmission at speeds up to 10Mbps (million bits per second). Today”s Ethernet can operate at 10, 100, and even 1Gbps (billion bits per second)

Ethernet Modem
An external modem that connects to the PC via a 10/100baseT Ethernet connection. The users PC must support Ethernet to use this modem. The users PC must have 10/100baseT included, or the user must install an Ethernet NIC

A computer system that reformats and transfers data between applications or networks that use different protocols. Gateways provide an address translation service

HTTP – (HyperText Transfer Protocol)
The protocol for moving hypertext files across the Internet. Requires a HTTP client program on one end and an HTTP server program (such as Apache) on the other end. HTTP is the most important protocol used in the World Wide Web (WWW)

ICASA stands for the Independent Communications Authority of South Africa. ICASA is the regulator of the telecommunications and broadcasting sectors in South Africa

The largest computer network in the world, using the IP protocol suite. The Internet provides file transfer, remote login, email, news, and other services and is becoming the predominant method of connecting people and businesses” computers

IP (Internet Protocol)
IP allows a data packet to traverse multiple networks on the way to its final destination. Internet Protocol (IP) Address A 32-bit number assigned to any computing device that uses the Internet Protocol (4 decimal fields separated by periods, e.g., 123.4.567.8

IPv4 — (Internet Protocol, version 4)
The most widely used version of the Internet Protocol (the “IP” part of TCP/IP.)
IPv4 allows for a theoretical maximum of approximately four billion IP Numbers (technically 232), but the actual number is far less due to inefficiencies in the way blocks of numbers are handled by networks. The gradual adoption of IPv6 will solve this problem
IPv6 — (Internet Protocol, version 6)
The successor to IPv4. Already deployed in some cases and gradually spreading, IPv6 provides a huge number of available IP Numbers – over a sextillion addresses (theoretically 2128). IPv6 allows every device on the planet to have its own IP Number

An internal Internet designed to be used within the confines of a company, university or organisation (outside users cannot access the entity`s Intranet)

ISDN Integrated Services Digital Network
An early dial-up predecessor of the DSL family that uses ISDN transmission technology to support up to 128 Kbps symmetrical service. ISDN is a usage-based service (tariffed) offered by the telephone companies and is very expensive relative to DSL

ISP (Internet Service Provider)
An ISP is a telecommunications company that sells Internet access services and other products to end users

Kilobits per second (Kbps)
Kilobits-per-second means thousands of bits per second. This is a way of describing the speed of an Internet connection (representing the number of bits transmitted per second). Typical modems operate at speeds between 9.6 Kbps and 56.0 Kbps

The time it takes a data packet to move across a network connection

Local Area Network (LAN)
Typically a LAN is used within a single location, building, or set of buildings. It enables communication between computers and the sharing of local resources such as printers, CD readers, databases, and file servers

Megabits per second (Mbps)
Megabits per second means millions of bits per second. Ethernet LANs operate at speeds up to 1Gbps. A T1 WAN connection operates at 1.544 Mbps

Stands for modulator/demodulator. A modem is a data communications device that connects a computer to the telephone network. A modem converts analog waveforms into digital data and vice versa. Digital or ISDN modems, also called Terminal Adapters, are used to connect computers to digital ISDN lines

Network Interface Card (NIC)
A standard Ethernet card (10baseT, or 100baseT) used to connect to an Ethernet modem, an Ethernet connected ADSL router, or other Ethernet connected interface device. “NIC” does not refer to an ADSL modem

A formatted unit of data transmitted on a network. Usually a piece of a larger file

PCI Modem
Sometimes referred to as an ADSL NIC, this modem connects inside the PC, into a PCI slot

Plain Old Telephone Service (POTS)
Basic voice telephone service is called POTS

Point-to-Point Protocol
The TCP/IP protocol that enables point to point connectivity to the Internet

A location for passing data in and out of a device

Point-to-Point Protocol over Ethernet (PPPoE)
Point to Point data connectivity over Ethernet. Can be used by one or multiple computers to share a single DSL connection

An explanation of message formats along with the rules systems must follow to exchange messages. Standard protocols enable different computers to communicate

(QoS) Quality of Service
QoS is the measure of the quality of service provided by a communications company

A telephone-industry standard connector type, usually contains four pins, for two pairs (telephone lines)

A telephone-industry standard connector type, usually containing eight pins

A device that connects (routes) multiple computer networks through IP addressing information contained in the IP packet. A DSL router routes packet data between a network and the Internet via the DSL connection

Serial Port
A port found on most computers through which data flows to and from a serial device. Typically used for low speed communications to peripherals

The splitter device separates the DSL data service from your analogue (POTS) telephone service. Your DSL service and telephone service will not affect each other.
The line from the exchange to your premises carries direct current to power the telephone, low frequency alternating current to ring the telephone, voice frequency conversation signals, and high frequency DSL signals. The DSL signals are up to ten times the voltage of voice and use much higher frequencies than ordinary telecommunications devices (telephones, fax machines, modems, alarm systems, etc). The splitter and or filter protects these devices from the DSL signals

Static IP address
A static Internet Protocol address that doesn`t change every time you log on to the Internet. A static IP address is required to run your own email server (SMTP), Virtual Private Network or remote communications applications

Subnet Mask
A 32-bit number to specify which part of an address is the network number, and which part is the host address

TCP/IP (Transmission Control Protocol/Internet Protocol)
Protocols developed by the U.S. Department of Defense in the 1970s to connect different computer networks. Essentially, these protocols are the basis of the Internet

Web Africa`s instant messaging application

An alternative to downloading large files such as audio and video. Streaming allows users to commence playback whilst the remaining file is downloading in the background

A virtual terminal protocol that enables the user to connect to other computers on the Internet

USB Modem
This is an external modem that connects to the PC via USB. There is a USB cable used between the PC and the modem

(VPN) Virtual Private Network
A VPN is a software defined private network. A way to deliver private data safely over a public network, such as the Internet. The data traveling between two hosts are encrypted for privacy

Wall Jack
A small outlet used to tap into telephone wall cable. An RJ”2″1 wall jack usually has four pins; an RJ-45 wall jack usually has eight pins

Web Africa Realm
An ADSL service that allows a user to identify their ADSL account name/s with a custom name brand. Associated ADSL usernames are formatted similarly to email addresses, such as username@customrealm. Web Africa`s clients use the WAADSL realm, formatted as username@wadsl

Wired Equivalent Privacy. Wireless encryption providing security against hackers and protecting data sent over wireless networks

Wide-Area Network (WAN)
A WAN is typically constructed to span cities and countries and links business network nodes. The Internet is considered a wide area network

Newer, more advanced method of encryption for wireless networks. Provides more security than WEP

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