Null-modem emulator 3.0

Null-modem emulator (com0com) by Vyacheslav Frolov is an open-source Windows driver that creates linked pairs of virtual COM ports, emulating a classic null-modem cable. Data written to one port instantly appears on its paired port, allowing two serial applications to communicate on the same PC without physical hardware. The emulator supports multiple port pairs, user-defined port names, standard serial line settings (baud rate, data bits, parity, stop bits), and hardware/software flow control, with full emulation of control signals such as DTR/DSR, RTS/CTS, DCD, and RI. Optional companion utilities can bridge virtual ports to real serial devices, route traffic between several ports, or carry serial data over TCP/IP, which is useful for remote testing and integration. Typical uses include developing, debugging, and automating legacy serial software; connecting SCADA/PLC, POS, GPS/NMEA, and ham radio applications; and building reproducible test rigs in labs and CI environments. Lightweight and reliable, it streamlines serial workflows while eliminating the need for physical cables.

Null-modem emulator is developed by Vyacheslav Frolov and is used by 23 users of Software Informer. The most popular version of this product among our users is 3.0.