Operating Instructions

Chapter 3 – Startring EasyComm
Siemens Building Technologies, Inc. 11
USB to RS232 Serial interface
As more USB devices have become available, many PC manufacturers no longer
supply a RS232 Serial Communications port by default but include multiple USB
ports for ease of use. There are many manufacturers of USB to serial interfaces; this
document is geared toward the SBT product (P/N: PXA-USBADAPTER) as this unit
has been tested. However, these steps should work with any USB to serial interface.
When a USB to RS232 Serial Interface is first inserted into an USB port the operating
system will prompt for installation and when complete, assign it a new COM port
number that was previously not used. This COM port number depends on the
number of USB interfaces that the computer has as well as the devices that were
previously used on the computer.
The COM port number of the USB to RS232 Serial interface must be known in order
to select the correct COM port in the EasyComm software to establish the online
connection.
This COM port number can be checked in the Device Manager and/or modified as
required.
To verify the COM port number assigned by the operating system, complete the
following steps:
1. From the Start Menu, select Settings … Control Panel (See Figure 10).
Figure 10.