Default echo transform: ASCII lowercase letters become uppercase; every other byte passes through unchanged.
Bytes the napplet wrote.
Bytes the mock device sends back.
mockSerialEcho([112, 105, 110, 103, 10]); // [80, 73, 78, 71, 10] — "PING\n" Copy
mockSerialEcho([112, 105, 110, 103, 10]); // [80, 73, 78, 71, 10] — "PING\n"
Default echo transform: ASCII lowercase letters become uppercase; every other byte passes through unchanged.