The idea is to let computers talk to each other without wires. These days there are a lots of wireless protocols and frequencies available. Well known protocols are Wifi & Bluetooth, but there are a lot more.

HC08 Bluetooth transceiver on Cosey robot

• nRF24L01P; 2.4GHz transceiver from Nordic semiconductor
• Mesh network; Implementation example of an extensible node interpreter.
• Other transceivers; An overview of available transceivers on different frequencies (or in a webshop).