Hardware Reference
In-Depth Information
Analogue and Digital
Inside most computers you will ind digital signals - that is, signals where it only matters if
they are on or off. Usually there is a difference of a few volts between a signal being on or
off. Data is sent by a code of ons and offs, typically referred to as 1s and 0s. A small change
in voltage due to radio or magnetic interference is usually not large enough to change the
meaning.
Analogue signals tend to only be used in modern computers where they have to connect
with something physical such as a monitor or speakers. An analogue signal typically repre-
sents data as a continuous range of voltages. As such, a small change in voltage means a
different value will be read. This means the data can be changed by electrical interference.
VGA monitors represent different colours with different voltages. Consequently, any inter-
ference will affect what is shown on the screen, and the image is degraded! Small amounts
of interference will have no effect on digital data for HDMI. However, if the interference is
strong enough, then all data will be corrupted and no image will be transmitted.
Connecting via Composite
If your display only has a connector for composite video, you need a phono-to-phono
cable that plugs in to the yellow connector on the top of the Raspberry Pi as shown in
Figure 1-8. Be aware that composite is an old technology and may produce a poor quality
display.
Connecting to a Network
he Raspberry Pi has an Ethernet socket that allows your Pi to connect to the Internet or
your home network. You can download new software and updates, or browse the web. You
could even run your own web server!
 
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