## Virtual Device Driver Reference for OS/2

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### Virtual COM Device Driver

The virtual COM device driver (VCOM) consists of virtual support for the serial communication I/O ports, and for the serial channel-related BIOS entry points. It provides support in each DOS session for up to four COM ports. In addition, this component allows existing DOS applications, which access communications channels by direct access to the I/O ports or by normal BIOS calls, to operate without change.

The VCOM only supports access to communication channels that are physically present on a given system. This does not include support for accessing communication devices that can be redirected by network software. From the perspective of the DOS session, the VCOM supports access through:

BIOS
I/O address space