Free com4 software for windows

Async Toolbox is a freeware interrupt driven communications library for C. Baud to 115200,COM1-COM4, simultaneous 2 port operation. Includes DATAMON.EXE: used to interface 2 serial devices, capture data, shows logic status of lines, and has an autobaud detection mode. Register for full source code, Digiboard (32 ports), 3 other utilities, prototypes, make files, batch files to create all memory models, Borland C & Microsoft C.
This package of asynchronous communications tools for IBM (COM1-COM4) and Digiboard (intelligent communications hardware, up to 32 ports) hardware, consists of library (.LIB) files for each memory model and for both IBM and Digiboard hardware. It also includes all of the source files, header files (with prototypes) and MAKE files needed to generate the various libraries. Batch files are included for calling make with appropriate flags for each supported compiles.
The "shareware" version comes with the small memory model library only (ASYNCS.LIB). Header files with module prototypes for the library routines are included. A test program (TEST.C) is included for testing the library on your system, and demonstrating the ease of use of the tools.
No other source code is provided with the shareware version or support for Digiboard hardware. Shareware versions are available for Borland C (C++) and Microsoft C (C++).