Charwat defines communication channel as follows:
``In general, a communication channel is a connection between one sending source and one receiving sink. In the human body a communication channel is formed by the sense organs, the nerve tracts, the cerebrum, and the muscles. In case of competing sensations at different sense organs there is one channel preferred.The following figure shows estimated capacities of human information reception, processing, and output summarized over all communication channels :
There is no total independence between the communication channels. For example: the capacity of received information coded with combined visual and auditive signals does not reach the sum of the single channels' capacities.''
Some channel capacities are mentioned in :
Table 1.2 : Capacities of different human input channels (taken from )
Most probably, these channel capacities originated from the Weber, Fechner, and Stevens laws of psychophysics. Therefore, their work will be reviewed here very briefly.