The IC-7760 acknowledges the 1A 06 data-mode command and stays in USB-D anyway, which left the operator unable to get back to plain USB from the console at all. After every mode set the flag is read back; on a mismatch it is said again with 0x26 — mode, data flag and filter in one frame, the form the newer rigs actually honour. Only on a mismatch, so rigs that predate 0x26 never see the command.