If you own an old unit and wish to get the new feature just order this preprogrammed chip.
Replace the old chip with it and you have the following new features:
- The mute feature now works even better than before eliminating the nasty switch-popp noise.
- A new feature has been added: Switch#6 (unused before) now can toggle a full unit mute. When the switch is pressed the unit gets totally silent until it is pressed again.