Winsoft ComPort v6.5 Full Source for Delphi/C++ Builder 5 - 11 and Lazarus
Component for serial communication for Windows.
Communication with devices connected to serial port
Easy of use and very powerful
Uses multithreading and overlapping for maximum performance
Supports Delphi/C++ Builder 5 - 11 and Lazarus 2.0.12
Source code included in registered version
Royalty free distribution in applications