All information must be transmitted from one place to another in order for it to be received across the globe.
There are three types of data transmission:
Simplex – One way transmission only. A one way system. For example, a radio.
Half duplex A two-way transmission, but it only allows one way at a time. For example a walkie-talkie.
Duplex (or full-duplex)- Two way transmission, that allows information to be transmitted at the same time. For example, a telephone.