Re: DLL Communication Interface: Win32 DLL <-> .NET class library

Hello,

I need to an TCP/IP Interface for communication with an embedded
device.
Since I have two different design ideas in mind, I am wondering
whether
you could give me some hints to decide:

Requirements:
- Interface should be used for company internal purposes/software but
also
  as an interface for our customers -> interface should be a DLL
- internally, the interface should only be used with C# Applications
- our customers want to use the interface with "native" C++, VB6, VBS,
  C#, VB.NET, Labview, ...

Design 1:
- implement the interface as .NET class library in C#
- expose this .NET class library as COM dll
  (whatever this means exactly...) so that it can be used by
  C++, VB6, VBS, ...
- advantage: easy implementation of the interface in C#;
  easy debugging
- disadvantage/open issue: what does it mean to expose the
  interface as COM dll (esp. in terms of effort); does
  exposing as COM dll really provide an interface for all
  possible applications? how can this COM interface be used?

Design 2:
- implement the interface in C++ as standard Win32-dll
- provide a C# wrapper class (maybe compiled as .net class library)
  mainly for internal purposes
- advantage: well-known win32-dll-interface -> our customers
  know how to use it and there are no tradeoffs
- disadvantage: complex socket programming in C++ required;
  C# wrapper required; more complex software debugging

Which design would you prefer? Why? Could you give
me some decision guidance, please?!