Winpcin is not usually sold as a standalone retail product. Instead, it is distributed by Siemens as part of the that comes with new Siemens CNC system installations. If you are looking to obtain it, you have a few options:
is a communication software tool designed to transfer data between a PC and Siemens SINUMERIK CNC controllers—most commonly the 802C, 802D, 802S, 810D, and 840D series. It serves as a modern Windows-based successor to the older DOS-based PCIN tool. Siemens Winpcin