3M SIP2 Resources and Implemetations - Standard Interchange Protocol

Definition in PDF : http://bibliotecaeupo.es/utils/SIP2/sip2_docs/sip2_developers_guide.pdf

PHP Implemetation : https://code.google.com/p/php-sip2/source/browse/trunk/sip2.class.php

Simple 3M SIP2 Standard Interchange Protocol implementation in perl : https://github.com/dpavlin/Biblio-SIP2

SIP2 Client in C# : https://github.com/NiceAndNerdy/SIP2.NET

Definitions and Examples from OCLC http://www.oclc.org/support/help/olib/900/Content/System/Supported%20SIP2%20Messages.htm#63_(Patron_Information)

MS Asynchronous Server Socket Example :
https://msdn.microsoft.com/en-us/library/fx6588te(v=vs.110).aspx
and Explanation of the sampe : https://msdn.microsoft.com/en-us/library/5w7b7x5f(v=vs.110).aspx

A TcpServer like the One in Delphi on CodeProject , looks great: http://www.codeproject.com/Articles/488668/Csharp-TCP-Server
The Server App freezes on Invoke so replace it with BeginInvoke methd.

Another TCP Server Example : http://sonyarouje.com/2011/11/25/multi-client-asynchronous-tcp-server/