+\begin{itemize}\itemsep=0pt
+\item \helpref{wxSocketEvent}{wxsocketevent},
+\helpref{wxSocketBase}{wxsocketbase},
+\helpref{wxSocketClient}{wxsocketclient},
+\helpref{wxSocketServer}{wxsocketserver}: classes for the low-level TCP/IP API.
+\item \helpref{wxProtocol}{wxprotocol}, \helpref{wxURL}{wxurl}, \helpref{wxFTP}{wxftp}, wxHTTP: classes
+for programming popular Internet protocols.
+\end{itemize}
+
+Further information on these classes will be available in due course.
+
+wxWindows has a high-level protocol based on Windows DDE.
+There are two implementations of this DDE-like protocol:
+one using real DDE running on Windows only, and another using TCP/IP (sockets) that runs
+on most platforms. Since the API is the same apart from the names of the classes, you
+should find it easy to switch between the two implementations.
+
+The following description refers to 'DDE' but remember that the equivalent wxTCP... classes
+can be used in much the same way.
+
+Three classes are central to the DDE API: