--- a/rs232.rst	Wed Dec 15 23:01:55 2010 +0200
+++ b/rs232.rst	Wed Dec 15 23:11:41 2010 +0200
@@ -1,5 +1,18 @@
 -*- mode: outline -*-
 
+* Pinout.
+
+Rx/Tx
+RTS/CTS/DTR/DSR
+
+* Level signals converts.
+
+** MAX 232.
+
+From an RS-232 serial port to signals suitable for use in TTL circuit.
+
+  http://en.wikipedia.org/wiki/MAX232
+
 * USB to COM chip.
 
 ** PL-2303.