5 The processes
My description of the three subsystems of 'means of conveying a message' has indicated some important processes that each carries out. These are shown in Figure 8. The key processes are those that will always be carried out and they are shown in bold; the other processes may or may not be performed. (I have used this scheme of bold text for essential processes in all block diagrams.)
Activity 5 (exploratory)
Look at the processes listed for the transmitter in Figure 8.
Now reread my two paragraphs about the transmitter. Underline the processes carried out by the transmitter.
Repeat (1) and (2) for both the network and the receiver.
Here is my paragraph about the transmitter, amended with the processes underlined.
'The transmitter receives a message from User 1 and manipulates it into data which can be sent into the network. The transmitter may also store or retrieve data relating to the message.
'In the mobile phone system, the transmitter, which is User l's mobile phone, receives a message from User 1 in the form of sound. It manipulates the incoming sound into a data format suitable for sending into the mobile phone network. Even basic models of mobile phone handsets can store names and telephone numbers, so in this example the transmitter is also storing and retrieving data.'
I'll leave you to underline the processes for network and receiver yourself.