System and operating method thereof

A system comprising:

• a host device including a first transmitter and a first receiver;
• and
• a data storage device configured to communicate with the host device and including a second transmitter and a second receiver,
• wherein the host device and the data storage device are configured to perform a first equalization operation including a first phase, a second phase, a third phase, and a fourth phase, and to perform a second equalization operation after the first equalization operation when at least one of the first receiver and the second receiver detects an error,
• wherein the second receiver is configured to perform, in the third phase, a signal tuning operation on the first transmitter,
• wherein the first receiver is configured to perform, in the fourth phase, a signal tuning operation on the second transmitter,
• wherein the host device is configured to, before entering the second equalization operation, transmit, to the data storage device, phase information indicating the fourth phase when the first receiver detects the error, and the data storage device is configured to, before entering the second equalization operation, transmit, to the host device, phase information indicating the third phase when the second receiver detects the error, and
• wherein the host device and the data storage device are configured to perform the second equalization operation by proceeding with one or more phases indicated by exchanged phase information.