--- a/rs232.rst	Fri Dec 17 12:16:34 2010 +0200
+++ b/rs232.rst	Sat Dec 18 17:01:11 2010 +0200
@@ -1,9 +1,24 @@
 -*- 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.
 
+  http://www.prolific.com.tw/eng/products.asp?id=59
+                about/overview
   http://www.prolific.com.tw/eng/downloads.asp?ID=23
                 datasheet download page
   http://www.prolific.com.tw/eng/downloads.asp?id=31