The device used on a Wide Area Network (WAN) to convert synchronous serial signals into digital signals is called a **CSU/DSU** (Channel Service Unit/Data Service Unit).
Here's why:
1. **CSU/DSU**: It stands for Channel Service Unit/Data Service Unit. This device is commonly used on WAN connections to convert the synchronous serial signals from a router into digital signals that can be transmitted over a digital communication line.
2. **Function**: The CSU/DSU performs the vital functions of ensuring proper signal quality, error detection, and synchronization between the transmitting and receiving devices on the WAN connection.
3. **Importance**: In WAN environments, the CSU/DSU is crucial as it bridges the gap between the customer's equipment (router) and the service provider's network, ensuring reliable and efficient data transmission.
In summary, the CSU/DSU is the device used on a WAN to convert synchronous serial signals into digital signals, playing a significant role in maintaining the integrity and performance of data transmission over wide-area networks.
