Introduction

Hardware means physical devices, 

• However in regard to transmitting and receiving we also include electro-magnetic waves (used to represent data) as physical components of the system. 
• Hence a wire is a physical component and so to is the signal moving down the wire.

Before we commence, let us consider a general overview of the communication hardware present in a typical system. 

To simplify our overview, we use an example home network that includes a connection to the Internet (see Fig 8.15). This example could easily be expanded to represent much larger system configurations.

Firstly transmitting and receiving processes are occurring between components within each computer. For example Mum’s computer is transferring data from RAM to the CPU whilst she surfs the net. Therefore we examine the various busses on the motherboard. 

Secondly, Mum’s computer sends data to the printer and the Kid’s computer communicates with the digital camera. Communication with external devices occurs via expansion slots and ports, hence we examine examples of these components. 

Thirdly modems are used to connect to other remote computers (usually over the Internet. In Fig 8.15 the modem connects the LAN (Local Area Network) to the Internet. Modems come in various types; for example cable, satellite, ADSL and dial-up modems. We examine the processes modems perform, in particular the modulation and demodulation of signals. 

Finally we discuss network hardware for local area networks (LANs) and wide area networks (WANs). Our discussions in regard to networks centre on the hardware tools required rather than their detailed operation.

In summary, we examine hardware for transmitting and receiving in regard to:

• Communication within a computer (the system or internal bus).
• Communication with external devices (external buses)
• The role of modems.
• Local area networks (LANs).
• Wide area networks (WANs).