Connections between computers on a network can be wired or wireless.
Computers can make a wireless connection if they have a wireless NIC. A wireless router provides a connection with the physical network. A computer device needs to be within range of the router to get access. A wireless connection uses radio signals to send data across networks. The wireless adapter converts the data into a radio signal and the wireless receiver decodes it so that the computer can understand it.
Wireless transmissions can be intercepted by anyone within range of the router. Access can also be restricted to specific MAC addresses, and transmissions are usually encrypted using a key that works with WPA (wi-fi protected access).