Features of WSC4VB include: Supports 256 ports. Can control multiple ports simultaneously. Fully thread safe, port re-entrant, modem control, serial line status and control, and ANSI emulation. Uses the standard Windows API to communicate with any device connected to a RS232 serial port. Supports virtual serial ports (USB to serial converter, Bluetooth serial). State driven Xmodem and Ymodem on multiple ports simultaneously (up to 256 connections). Can send Windows messages on completion of events (incoming character). Includes 49 functions plus modem control. Supports any baud rate. Ability to specify the parity, word size, and number of stop bits. Includes multiple Visual Basic example programs. Does not depend on support libraries (calls to core Windows API functions only). Royalty free distribution with your compiled application. C source code is available.