1.2 Data Communications: Example
The components described in the Shannon/Weaver model can be examined by looking at a telephone conversation between two people. The sender (or source) is the person who initiates the call by lifting the telephone handset and dialling a unique number and the receiver (or destination) is the person who answers the ringing telephone.
When the sender speaks into the telephone’s mouthpiece the speech is converted (or encoded) into an electrical signal that can be sent down the telephone line. At the receiver’s end the encoded message is decoded back into human speech. The channel being used to transmit the message is the Public Switched Telephone Network (PSTN), and the message is the content of the telephone conversation.
The Shannon/Weaver model also includes an indication that successful communication may be affected by noise or interference. This is a common problem in data communications and typically means that all data transmission systems must have inbuilt error detection and correction facilities to try and minimise the effects of interference.