Final answer:
A CSU/DSU is the device specifically used for making WAN connections, translating between the LAN and WAN networks.
Step-by-step explanation:
The device used to make WAN (Wide Area Network) connections is a CSU/DSU (Channel Service Unit/Data Service Unit). This device connects a digital leased line from a telecommunications carrier to a router and is essential for connection to the Internet.
While a router is used to direct data packets between different networks, including WANs, the CSU/DSU acts as a translator between the local area network (LAN) and the WAN. A 10BaseT hub is used to connect multiple Ethernet devices in a LAN, and an Ethernet repeater extends the reach of an Ethernet network by regenerating the signal. It is the CSU/DSU that serves the specific purpose of making WAN connections.