At some point in the past, NIST supposedly dropped the on-time marker.
A comment was added as was support for a second format without the
on-time marker.  That was partially removeed in 2011 in commit
ef0eee67, but vestiges remained.

The documentation did not match the code: backup and auto were reversed.

Also, in the "Driver Options" section, "mode" was listed as "Not used by
this driver", which is incorrect.

It took me a while to figure out how the "phone" bit worked, even with
the documentation.  An example would have saved me time.