work on docs

docs/radiocom2000.html

@@ -28,6 +28,12 @@ History
 How it works
 </p>
 
+<p>
+Please refer to
+<a href="standard_r2000_by_jolly.pdf">standard_r2000_by_jolly.pdf</a>
+for a description of the standard.
+</p>
+
 <p class="toppic">
 <a name="basestation"></a>
 Setup of a base station