A system and method for detecting errors in high-speed asymmetric interfaces are described. Embodiments include transmitting digital data between a first system component and a second system component over a bidirectional interface, wherein the first component is significantly more intelligent than the second component. The first component controls many operations of the second component, including receiving a signature from the second component over an existing line of the interface. The signature received is compared to a signature stored by the first component. Both signatures correspond to a transaction over the interface. Based on the comparison, the first component determines whether the transaction was successful, and directs the second component as necessary.