--- /dev/null
+<para>
+This option transfers the contents of the unit's data log. The data is
+downloaded as a single track.
+</para>
+<para>
+Only reading of the data log is supported, and you must use
+the <option>-t</option> option to receive any data.
+</para>
--- /dev/null
+<para>
+This option clears the datalogger in the receiver after doing the
+transfer.
+</para>
+<para>
+This is a convenient option to use in automated processes if you want
+to clear the device after receiving the data logger contents.
+</para>
--- /dev/null
+<para>
+ This format is for SBP datalog files saved to the SD card by
+ the Locosys GT-11/BGT-11/GT-31/BGT-31.
+</para>