Null-modem emulator (com0com) 3.0

Null-modem emulator (com0com) by Vyacheslav Frolov is a free, open-source virtual serial port driver for Windows. It creates pairs of virtual COM ports that behave like a hardware null‑modem cable, allowing two applications to communicate with each other as if they were connected by physical RS‑232 ports.

Key features:

• Creates virtual COM port pairs with customizable names and pin mappings
• Emulates control signals (RTS/CTS, DTR/DSR, DCD/RI) and supports typical serial settings
• Works on 32‑bit and 64‑bit Windows
• Includes companion tools (hub4com and com2tcp) for port sharing, data logging, and bridging serial data over TCP/IP

Common uses:

• Testing and debugging serial applications without physical hardware
• Replacing null‑modem cables in lab or production environments
• Connecting terminal emulators, modem simulators, SCADA/PLC software, GPS/CNC simulators, and other legacy serial tools

Benefits:

• No hardware required, easy to configure, and provides high throughput with low latency
• Ideal for developers, QA engineers, and system integrators working with serial-based software

Note: Installing the driver requires administrator privileges. On some 64‑bit systems, you may need a signed build of the driver, depending on your Windows configuration.

Null-modem emulator (com0com) is developed by Vyacheslav Frolov. The most popular versions of this product among our users are: 2.2 and 3.0. The name of the program executable file is Emulator.exe.