Types of communication
When devices communicate they use one of three methods; Simplex, half-duplex and duplex (full duplex).
Simplex communication is one way communication. A television remote uses infrared to communicate with the television, This is simplex communication as the television isn't communicating back. In other words, simplex communication is like a single lane full of traffic where no other cars can come through the other way. Another example would be a keyboard or a mouse.
Half - Duplex is where devices can talk to each other but not at the same time. Imagine a single lane with traffic lights. A walkie talkie uses half duplex communication.
Duplex communication is where there are two lanes of traffic and both lanes can go in their own direction at the same time. An example of duplex communication would be a mobile phone