@ - at, at sign, ape, cabbage, commercial at, cyclone, each, monkey, snail, rose, strudel, vortex, whorl, whirlpool. A symbol to which number 64 is assigned in ASCII characters; it is used in writing e-mail addresses to separate the user name from the domain in which their account is open. 

ADC – converting analogue into digital format, such as that the sound card performs when digitalizing a sound wave into a wave-type file.

ADN - (Advanced Digital Line) Digital line of the transfer speed, most often 56 kbps (kilobits per second). Rented line.

Address – each web page on the Internet is assigned a unique recognizable address. Address is also known as URL (Uniformed Resource Locator).

Analogue signal – continually changeable type of voltage or a wave shape, such as a sound wave etc.

Anonymous FTP – User gets access to a remote server through FTP (File Transport Protocol) without having a user account on the same server. When connecting to a server, a user will enter their e-mail address instead of a password, and the system supporting this service will assign the user a user name "anonymous".

ASCII - (American Standard Code for Information Interchange). Each character is assigned a six-bit, seven-bit or eight-bit code, depending on the desired range of ASCII character list.