The Ethernet specifications actually offer a number of different choices for cabling. The other common choice is coaxial cable, used for 10Base2. There are some important differences between the two. Twisted pair connects using RJ-45 modular plugs, which look like wider versions of standard telephone jack connectors. If you need to connect more devices, you can connect one hub to another.
Coaxial cable has a different set of requirements.
It connects using a bayonet-style connector, known as a BNC connector. A T-shape connector is attached to each network adapter, and cables connect the devices. At either end of the chain the T-connector must have a terminating resistor attached. There are advantages and disadvantages to the coaxial approach. If you want to add or remove systems on the network, you have to change the cabling to the adjacent systems in the chain, instead of just adding or removing a single cable to a central hub.