The following functions are decided by the human users of a voice networks during a conversation but must be controlled by the network in data communications:-
- Language used
- Signal strength (how loud to speak)
- When to repeat a message if it is not received or understood
- A voice network must, therefore, comply with layers 1 to 3 with layers 4 to 7 the responsibility of the user.
- A data network must comply with layers 1 to 6 with layer 7 the responsibility of the user.