Omega OMG-USB-SER-2 User Manual
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e-mail: info@omega.com
User’s Guide
OMG-USB-SER-2
Two Port RS-232/422/485 to USB Adaptor
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Manual No. M-3899
Contents
INTRODUCTION..........................................................................1
OVERVIEW................................................................................................1
WHAT ’S INCLUDED................................................................................ 1
INSTALLATION ..........................................................................2
OPERATING SYSTEM INSTALLATION ................................................. 2
SYSTEM INSTALLATION........................................................................2
CONFIGURATION........................................................................4
ORIGINAL CONFIGURATION..................................................................4
ELECTRICAL INTERFACE SELECTION.................................................4
SWITCH EXAMPLES................................................................................6
SWITCH EXAMPLES CONTINUED........................................................7
TECHNICAL DESCRIPTION.........................................................8
FEATURES ................................................................................................ 8
CONNECTOR PIN ASSIGNMENTS..........................................................8
RS-422/485 (DB 9 Male)................................................................8
RS-232 (DB-9 Male) ........................................................................8
SPECIFICATIONS ........................................................................9
ENVIRONMENTAL SPECIFICATIONS....................................................9
MANUFACTURING..................................................................................9
POWER CONSUMPTION..........................................................................9
MEAN TIME BETWEEN FAILURES (MTBF).......................................9
PHYSICAL DIMENSIONS..........................................................................9
APPENDIX A - TROUBLESHOOTING.........................................10
APPENDIX B - HOW TO GET ASSISTANCE..............................11
APPENDIX C - ELECTRICAL INTERFACE ...................................12
RS-232.....................................................................................................12
RS-422.....................................................................................................12
RS-485.....................................................................................................13
APPENDIX D - ASYNCHRONOUS COMMUNICATIONS ...............14
APPENDIX E - COMPLIANCE NOTICES .....................................15
FEDERAL COMMUNICATIONS COMMISSION STATEMENT ............ 15
CANADIAN RADIO INTERFERENCE REGULATIONS.........................15
EMC DIRECTIVE STATEMENT ........................................................... 16
Figures:
Figure 1: Switch SW2...........................................................................................5
Figure 2: RS422/485 Interface Configuration................................................6
Figure 3: Electrical Interface Configuration....................................................7
Figure 4 - Asynchronous Communications Bit Diagram.............................14
Introduction
Introduction
Overview
The OMG-USB-SER-2 equips the PC with 2 USB to RS-232/422/485
Asynchronous serial ports providing a versatile interface for common serial
needs. The advantage of this product over more traditional approaches is that it
does not require opening the computer case, nor does it require resources such
as I/O ports or IRQ’s. It does require a system that supports USB both in terms
of hardware and operating system.
What’s Included
The OMG-USB-SER-2 is shipped with the following items. If any of these items
is missing or damaged, contact the supplier.
• OMG-USB-SER-2 USB to RS-232/422/485 Serial I/O Adapter
• USB Cable Part Number CA179 for Connecting to Upstream
Host/Hub
• Software
OMG-USB-SER-2 Page 1
Installation
Installation
Operating System Installation
Choose Install Software at the beginning of the CD and install SeaCOM.
System Installation
The screen captures below are taken from a Windows 98 installation. Your
particular operating system may differ slightly from what is shown based on your
version of Windows.
The OMG-USB-SER-2 can be connected to any upstream type “A” port either at
the PC host or an upstream hub. The OMG-USB-SER-2 is hot pluggable,
m eaning there is no need to power down your computer prior to installation.
Connect the OMG-USB-SER-2 to an upstream host or hub.
The New Hardware Found wizard will now proceed to locate the appropriate
drivers. These drivers were installed during the SeaCOM software setup
procedure. Once the drivers are found a new window will pop up indicating the
installation of each of the four new ports.
If you view the system’s Device Manager, you should have new “COM” ports in
the Ports (COM & LPT) Device Class. This is shown on the following page.
OMG-USB-SER-2 Page 2
Installation
You can access your new COM: ports by using the assigned COM: identifiers as
shown above. In this case, it is COM 3 and 4. However, this assignment will vary
from system to system. At this point, the hardware is recognized and ready to
use.
OMG-USB-SER-2 Page 3
Configuration
Configuration
Original configuration
This device ships with the following configuration.
422 mode,
120 ohm termination,
1K ohm pull up on RX+
1K ohm pull down on RX-
In order to change this configuration the box must be opened. Do this by
removing the four screws located on the bottom. When reassembling please note
that the top and bottom are keyed to fit in only one direction.
Electrical Interface Selection
Each of the two ports on the OMG-USB-SER-2 can be individually configured as
an RS-232, RS-422, or RS-485 interface. This is selectable via the DIP switches
and DIP shunts. Each of the switch positions is described on the following page.
OMG-USB-SER-2 Page 4
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