I started a new thread on this since the earlier one was straying off on tangents. We took a long look at the HMa and it looks like we can add dweedle tone controls for frequency, mic levels and maybe roll off. We cannot mute or enable a Sleep mode, the circuits are not there to support those functions. Adding those circuits at this time would mean huge delays and additional, very costly approvals testing since we are already 99% finished with those tests at the lab (and have paid heavily to do so). So, we have "pulled the trigger" on writing the code. It remains to be seen if the new code will be immediately available when we begin shipping but the HMa has a nice little USB port, so you can update anytime we come up with the new firmware. Fair warning - we may yet encounter some other technical problem but we are committing to the change as of this morning.
Thanks for all the input - great ideas!