SuperCom TCP/IP(site info)
An optimized, thread based, Low Level Engine, which handles simultaneously connections, buffers data and generates events. Optimized threads reduce CPU load to minimum. A dual mode programming interface is provided (DLL and ActiveX). [Commercial]
http://www.adontec.com/supert_e.htm
3.
ConvertSpot(site info)
Provide COM/DLL components to convert PDF to XML, PDF to text, MS Word to text, PowerPoint to text, Excel to text, Excel to xml, Excel to CSV.
http://www.convertspot.com
4.
DC Micro Development, Inc.(site info)
Cross-platform development libraries for C/C++ and Visual Basic. Products include libraries for data compression, TCP/IP protocols, dynamic html emission, and help authoring software.
http://www.dcmicro.com/