<para>
Magellan's protocol specification strongly encourages the use of software
acknowledgements on every packets.   This is a simple "this is what I think
I heard.  If you agree that I heard it correctly, let's go to the next packet"
handshake that is used to ensure the integrity of the data transfer.
</para>
<para>
Certain firmware versions have problems handling this which makes transfers
unnecessarily slow.  Transfers on all units at high serial speeds  are also
severely restricted by this process. 
</para>
<para>
In controlled environments (good cables, low electrical noise, receiving
from the unit, not doing donuts with the unit set to "track up" at a 150
mile scale with 500 waypoints on the screen) it is sometimes useful to 
release that safety belt by using the "noack" suboption.
</para>
