>Hi,
>
>I am looking for a good solid communication library for use
>with VFP5, VB5 and VC5++. It should had z-modem transfer protocol
>and other like ftp transfer feature and other.

Rather than a comm library, I'd investigate using a scriptable, programmable communications package such as ProComm or Telix - you can develop the scripts interactively, independent of language, and then simply invoke the comm package with appropriate scripting. It reduces the language implementation dependent issues, gives an interactive process development and testing mode, and does not require you to learn all the detailed requirements for communications programming. Licensing is straightforward - the client purchases the required product, and the comm product vendor can provide knowledgable support where issues that may not be familiar to you.

If you undertake writing detailed comm functionality and are not well-acquainted with all the issues, you're opening yourself up to a world of hurt. YMMV - I wrote a considerable amount of communications programs in the past, and even with a library, you really have a need to understand a pretty significant amount of technology.