An echo check is a simple form of error checking in Computer Science and networking where the received data is immediately retransmitted back to the sender. If the sender receives the same data back they sent then they know it is highly likely that the receiver has received the data correctly.
In network troubleshooting, an administrator might use an echo check to verify the connectivity and integrity of a network connection. They send a test signal, and if they receive the same signal back, it indicates that the network link is operational. If they don't receive the expected echo, it suggests a problem with the connection or data transmission.
