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Using VCOM
Page 60
AirborneDirect™ Serial Bridge User’s Guide
100-8006-152G
Quatech, Inc. Confidential
DESCRIPTION OF VCOM COMPONENTS
The VCOM components consist of the following:
Network Management Service (NMS)
VCOM Serial Device Driver
VCOM Configuration Utility
Network Management Service (NMS)
The Network Management Service (NMS) is a Microsoft
®
Windows
®
service that performs the
network-related operations for the VCOM serial device driver.
The NMS has two operating modes, pass-through mode and communications mode. In pass-
through mode, the NMS authenticates with the Bridge and establishes a pass-through
connection with it. In this mode, data sent to the Bridge is forwarded to the host serial device.
In communications mode, the NMS establishes only a Transmission Control Protocol (TCP)
connection with the Bridge. The application or DLL is responsible for authenticating with the
Bridge, sending commands to it, and interpreting responses from it. In this mode the NMS is a
pass-through for communications through an application or DLL.
Note:
Communications mode is only available through the DPAC Technologies’
developer program. For more information, please contact DPAC
Technologies.
VCOM Serial Device Driver
The heart of the VCOM software is the VCOM serial device driver (
dpacvcom.sys
). This
device driver is a fully functional Windows
®
XP/2000 serial port driver that acts as a buffer
manager, enabling data to pass from an application through the device driver to the NMS. The
VCOM application accesses the device driver through the same standard serial communications
port method used to access the standard serial device driver.
This device driver presents the following interfaces:
A standard serial port interface to the Windows
®
XP/2000 operating system. This
interface standard is known as the VCOM API. All serial port accesses, irrespective of
programming paradigm (C/C++, Visual Basic, etc.), use this interface to access serial
ports. Through this interface a virtual serial port looks like a physical serial port on a
system.
A proprietary interface (unique to VCOM) that allows the application control of
serial port functions and the ability to map them to physical IP addresses.