An interface is usually provided by a card which contains ports for input and output devices,
plus processing and memory microchips. In effect it translates
one form of communication from an external input device into that
which can be understood by the computer and then, if necessary,
into another that can be sent to any special output device, or
another computer. An interface card may be inserted in one of the
slots provided inside the computer or it may be external with its
own power supply and plugged into the computer's serial
some common examples:
- needed for Internet, email, fax and video-conferencing
communications using telephone cables. It converts outgoing
digital signals from the computer into analogue audio tones which
can travel along the telephone wires, and the reverse for
modem can transmit and receive at a speed of 33,600 bits per
second (bps) which is about 4200 bytes (or characters) a second.
This is about one page of text, so it is much cheaper and
somewhat quicker than ordinary mail.
Card - for
music or speech from programs, CD-ROMs, and microphone. It
usually includes a MIDI interface for input from musical
MIDI (Musical Instrument
Digital Interface) - needed to connect musical instruments to
a computer so that the music played can be stored as a file,
displayed on screen, edited, printed or played back.
enables the computer to communicate with other computers linked
together by cable through the interface. Used for shared storage
of programs and work files, and for sharing printers.