A system includes a first device and a second device configured to exchange data packages over a bi-directional wireless communication channel, wherein the first device and the second device are configured for use by a user; wherein the first device is configured to provide a first data package, wherein the first data package belongs to a first packet category and comprises first audio data; wherein the first device is also configured to transmit the first data package to the second device, and receive a second data package belonging to the first packet category; and wherein the second data package comprises second audio data, a code indicating whether data in the second data package is corrupted or invalid, and an indicator indicating whether the first data package was successfully received by the second device or not.