Final answer:
To check for errors at the receiver, use parity checking. Add an additional bit to the message and check if the total number of 1s (including the parity bit) is even.
Step-by-step explanation:
To check for errors at the receiver, you can use a technique called parity checking. In this case, since the incoming message is a binary string (1111100111), you can use the parity bit to verify the correctness of the message. Parity checking involves adding an additional bit to the message so that the total number of 1s is either even (even parity) or odd (odd parity).
In even parity, if the total number of 1s (including the parity bit) is even, the message is considered error-free. In odd parity, if the total number of 1s (including the parity bit) is odd, the message is considered error-free. If the total number of 1s is odd or even, it indicates there is an error in the message.
In the given example, you can use even parity. Add an additional bit (0 or 1) to the binary string to make the total number of 1s even. For example, if you add a 0 at the end, the message becomes 11111001110. Now, you can verify the parity using the total number of 1s in the message. If it is even, there is no error. Otherwise, there is an error somewhere in the message.