The Personal Serial Communication Library for C/C++ DOS supports real and protected mode DOS, COM1 through COM20 to 115200, 4+ ports concurrently, many dumb multiport boards, 16550, 16650, 16750 UARTs, interrupt driven, RTS/CTS flow control, any UART address and IRQ, and all memory models.
Personal Serial Communications Library for C/C++ DOS supports Borland/Turbo C/C++, MIX Power C, and Microsoft C/C++ and Watcom C/C++.
The Personal Serial Communications Library for C/C++ (PCL4C) can be used in the development of real and protected mode applications running under DOS.