.NET,Mono, DotGNU, C#, VB, WebServices, SOAP, XML/XSLT/XPATH, ASP, ASP.NET, Java, JSP. VOIP, h323, SIP, ISDN, PRI, BRI, E1,T1,NT/TE-Mode, SW PBX-Systems, Asterisk, PBX4Linux. Linux, BSD, DOS, MS-Windows: 3.1-7, Win32, Win64, COM, ADO, WinForms, WPF. Exchange, Active-Directory, Samba, Hylafax, MS-SQL-Server,Oracle-DB,MySQL,PostGreSQL. Ethernet-Routers, Bridges, Cabling, embedded systems, MIPS, Geode, Opteron, WAN, MS/Open Office, Latex, Pascal. Delphi. C, C++, Perl, Prolog, x86/MIPS-Assembler. Presentations. Product development. Planning, Administration.