Omega RS-232 User Manual

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User’s Guide

OMG-ULTRACOMM2-PCI

Dual Port PCI RS-232/422/485 Interface Board

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WARNING: These products are not designed for use in, and should not be used for, patient-connected applications.

Contents

INTRODUCTION..........................................................................1

OVERVIEW................................................................................................1

WHAT ’S INCLUDED................................................................................ 1

FACTORY DEFAULT SETTINGS ............................................................ 1

CARD SETUP ..............................................................................2

RS-485 E NABLE MODES.........................................................................2

Interface Mode Examples J1B and J2B (continued).......................4

ADDRESS AND IRQ SELECTION............................................................4

LINE TERMINATION ............................................................................... 5

ELECTRICAL INTERFACE SELECTION.................................................6

CLOCK MODES........................................................................................7

BAUD RATES AND DIVISORS FOR THE ‘DIV1’ MODE ........................8

BAUD RATES AND DIVISORS FOR THE ‘DIV2’ MODE ........................9

INSTALLATION ........................................................................10

OPERATING SYSTEM INSTALLATION ............................................... 10

DOS.........................................................................................................10

WINDOWS 3.1X......................................................................................10

WINDOWS 95......................................................................................... 10

WINDOWS NT........................................................................................10

HARDWARE INSTALLATION ............................................................... 10

TECHNICAL DESCRIPTION.......................................................11

INTERRUPTS..........................................................................................11

WHY USE AN ISP?.................................................................................12

CONNECTOR PIN ASSIGNMENTS........................................................12

RS-232..................................................................................................12

RS-422/485..........................................................................................13

SPECIFICATIONS ......................................................................14

ENVIRONMENTAL SPECIFICATIONS..................................................14

MANUFACTURING ............................................................................... 14

POWER CONSUMPTION........................................................................14

MEAN TIME BETWEEN FAILURES (MTBF).....................................14

PHYSICAL DIMENSIONS........................................................................14

APPENDIX A - TROUBLESHOOTING.........................................15

APPENDIX B - HOW TO GET ASSISTANCE..............................16

APPENDIX C - ELECTRICAL INTERFACE ...................................17

RS-232.....................................................................................................17

RS-422.....................................................................................................17

RS-485.....................................................................................................18

APPENDIX D - ASYNCHRONOUS COMMUNICATIONS ...............19

APPENDIX E - SILK-SCREEN ....................................................20

APPENDIX F - COMPLIANCE NOTICES .....................................21

FEDERAL COMMUNICATIONS COMMISSION STATEMENT ............ 21

EMC DIRECTIVE STATEMENT ........................................................... 21

Figures

Figure 1- Headers J1B and J2B, RS-422..........................................................3

Figure 2 - Headers J1B and J2B, RS-485 ‘Auto’ Enabled, ‘No Echo’..........3

Figure 3 - Headers J1B and J2B, RS-485 ‘Auto’ Enabled, ‘Echo’................3

Figure 4 - Headers J1B and J2B, RS-485 ‘RTS’ Enabled, ‘No Echo’..........4

Figure 5 - Headers J1B and J2B, RS-485 ‘RTS’ Enabled, ‘Echo’................4

Figure 6 - Headers J1A and J2A, Line Termination.......................................5

Figure 7 Headers E1 - E4, Electrical Interface Selection...............................6

Figure 8 - Clocking Mode 'Divide By 4’............................................................7

Figure 9 - Clocking Mode 'Divide By 2’............................................................7

Figure 10 - Clocking Mode 'Divide By 1’..........................................................7

Figure 11 - Asynchronous Communications Bit Diagram..........................19

© 1998f Omega Engineering, Incorporated. All rights reserved.

Introduction

Introduction

Overview

The OMG-ULTRA COMM+2.PCI is a two channel PCI Bus serial I/O adapter for
the PC and compatibles. It provides two field selectable RS-232/422/485 serial
ports supporting data rates up to 460.8K bps.

Configure both ports as RS-232 for standard serial COM: port requirements.
Choose the RS-422 mode for long distance device connections up to 4000ft.
where noise immunity and high data integrity are essentia l. Select RS-485 and
capture data from multiple peripherals in a RS-485 multidrop network. Up to 31
RS-485 devices can be connected to each port to automate your data collection.
You can even mix the ports in any of the interface combinations to provide
maximum flexibility to your application.

In both RS-232 and RS-422 modes, the card works seamlessly with the standard
operating system serial driver. In RS-485 mode, our special auto-enable feature
allows the RS-485 ports to be viewed by the operating system as a COM: port.
This allows the standard COM: driver to be utilized for RS-485 communications.
Our on-board hardware automatically handles the RS-485 driver enable. UART
upgrades are available providing 32 and 64 byte FIFOs.

What’s Included

The OMG-ULTRA COMM+2.PCI is shipped with the following items. If any of
these items are missing or damaged, contact the supplier.

• OMG-ULTRA COMM+2.PCI Serial I/O Adapter

• Serial Utility Software

• User Manual

Factory Default Settings

The OMG-ULTRA COMM+2.PCI factory default settings are as follows:

Port # Electrical Specification

Port 1 RS-232
Port 2 RS-232

To install the OMG-ULTRA COMM+2.PCI using factory default settings, refer
to Installation on page 10.

For your reference, record installed OMG-ULTRA COMM+2.PCI settings below:

Port # Electrical Specification

Port 1
Port 2

Omega Engineering OMG-ULTRA COMM+2.PCI Page 1

Card Setup

Card Setup

In all cases J1x refers to settings for the first port and J2x refer to settings for
the second port.

RS-485 Enable Modes

RS-485 is ideal for multi-drop or network environments. RS-485 requires a tri-state
driver that will allow the electrical presence of the driver to be removed from the
line. The driver is in a tri-state or high impedance condition when this occurs.
Only one driver may be active at a time and the other driver(s) must be tri-stated.
The output modem control signal Request To Send (RTS) is typically used to
control the state of the driver. Some communication software packages refer to
RS-485 as RTS enable or RTS block mode transfer.

One of the unique features of the OMG-ULTRA COMM+2.PCI is the ability to
be RS-485 compatible without the need for special software or drivers. This
ability is especially useful in Windows, Windows NT, and OS/2 environments
where the lower level I/O control is abstracted from the application program. This
ability means that the user can effectively use the OMG-ULTRA COMM+2.PCI
in a RS-485 application with existing (i.e. standard RS-232) software drivers.

Headers J1B and J2B are used to control the RS-485 mode functions for the driver
circuit. The selections are ‘RTS’ enable (silk-screen ‘RT’) or ‘Auto’ enable (silk­screen ‘AT’). The ‘Auto’ enable feature automatically enables/disables the
RS-485 interface. The ‘RTS’ mode uses the ‘RTS’ modem control signal to
enable the RS-485 interface and provides backward compatibility with existing
software products.

Position 3 (silk-screen ‘NE’) of J1B and J2B is used to control the RS-485
enable/disable functions for the receiver circuit and determine the state of the
RS-422/485 driver. The RS-485 ‘Echo’ is the result of connecting the receiver
inputs to the transmitter outputs. Every time a character is transmitted; it is also
received. This can be beneficial if the software can handle echoing (i.e. using
received characters to throttle the transmitter) or it can confuse the system if the
software does not. To select the ‘No Echo’ mode select silk-screen position ‘NE’.

For RS-422/530/449 compatibility remove the jumpers at J1B and J2B.

Exampl es on the following pages describe all of the valid settings for J1B and
J2B.

Omega Engineering OMG-ULTRA COMM+2.PCI Page 2

Card Setup

Interface Mode Examples J1D – J4D

ATRTNE

Figure 1- Headers J1B and J2B, RS-422

ATRTNE

Figure 2 - Headers J1B and J2B, RS-485 ‘Auto’ Enabled, with ‘No Echo’

ATRTNE

Figure 3 - Headers J1B and J2B, RS-485 ‘Auto’ Enabled, with ‘Echo’

Omega Engineering OMG-ULTRA COMM+2.PCI Page 3

Card Setup

Interface Mode Examples J1B and J2B (continued)

ATRTNE

Figure 4 - Headers J1B and J2B, RS-485 ‘RTS’ Enabled, with ‘No Echo’

ATRTNE

Figure 5 - Headers J1B and J2B, RS-485 ‘RTS’ Enabled, with ‘Echo’

Address and IRQ selection

The OMG-ULTRA COMM+2.PCI is automatically assigned I/O addresses and
IRQs by your motherboard BIOS. Only the I/O address may be modified by the
user.

Adding or removing other hardware may change the assignment of I/O
addresses and IRQs.

Omega Engineering OMG-ULTRA COMM+2.PCI Page 4

Card Setup

Line Termination

Typically, each end of the RS-485 bus must have line terminating resistors
(RS-422 terminates at the receive end only). A 120-ohm resistor is across each
RS-530/422/485 input in addition to a 1K ohm pull-up/pull-down combination that
biases the receiver inputs. Headers J1A and J2A allow the user to customize this
interface to their specific requirements. Each jumper position corresponds to a
specific portion of the interface. If multiple OMG-ULTRA COMM+2.PCI
adapters are configured in a RS-485 network, only the boards on each end should
have jumpers T, P & P ON. Refer to the following table for each position’s
operation:

Name Function

P Adds or removes the 1K ohm pull-down resistor in the

RS-422/RS-485 receiver circuit (Receive data only).

P Adds or removes the 1K ohm pull-up resistor in the RS-422/RS-

485 receiver circuit (Receive data only).
T Adds or removes the 120 ohm termination.
L Connects the TX+ to RX+ for RS-485 two wire operation.
L Connects the TX- to RX- for RS-485 two wire operation.

P P T L L

Figure 6 - Headers J1A and J2A, Line Termination

Omega Engineering OMG-ULTRA COMM+2.PCI Page 5

Card Setup

Electrical Interface Selection

Each port on the OMG-ULTRA COMM+2.PCI has the ability to be used in either
RS-232 or RS-422/485. This is selectable via four 24 pin DIP-shunts at E1-E4.
Please use the following illustration to aid in the configuration of your electrical
interface.

RS-232RS-422

RS-232RS-422

RS-232

E1

Port 1

RS-232RS-422

E2

E3

Port 2

RS-232RS-422

E4

RS-232RS-422

E1

Port 1

E2

RS-232RS-422

E3

Port 2

E4

RS-232 and RS-422/485

E1

Port 1

E2

E3

Port 2

E4

RS-422/485

Figure 7 Headers E1 - E4, Electrical Interface Selection

Omega Engineering OMG-ULTRA COMM+2.PCI Page 6

Card Setup

Clock Modes

The OMG-ULTRA COMM+2.PCI employs a unique clocking option that allows
the end user to select from divide by 4, divide by 2 and divide by 1 clocking
modes. These modes are selected at Headers J1C through J4C.

To select the Baud rates commonly associated with COM: ports (i.e. 2400, 4800,
9600, 19.2, … 115.2K Bps ) place the jumper in the divide by 4 mode (silk-screen
DIV4).

DIV1

DIV2

DIV4

Figure 8 - Clocking Mode 'Divide By 4’

To double these rates up to a maximum rate for 230.4K bps place the jumper in
the divide by 2 (silk-screen DIV2) position.

DIV1

DIV2

DIV4

Figure 9 - Clocking Mode 'Divide By 2’

To select the maximum data rate (460.8K bps) place the jumper in the divide by 1
(silk-screen DIV1) position.

DIV1

DIV2

DIV4

Figure 10 - Clocking Mode 'Divide By 1’

Omega Engineering OMG-ULTRA COMM+2.PCI Page 7

Card Setup

Baud Rates and Divisors for the ‘Div1’ mode

The following table shows some common data rates and the rates you should
choose to match them if using the adapter in the ‘Div1’ mode.

For this Data Rate Choose this Data Rate

1200 bps 300 bps
2400 bps 600 bps
4800 bps 1200 bps
9600 bps 2400 bps

19.2K bps 4800 bps

57.6 K bps 14.4K bps

115.2 K bps 28.8K bps

230.4K bps 57.6 K bps

460.8K bps 115.2 K bps

If your communications package allows the use of Baud rate divisors, choose the
appropriate divisor from the following table:

For this Data Rate Choose this Divisor

1200 bps 384
2400 bps 192
4800 bps 96
9600 bps 48

19.2K bps 24

38.4K bps 12

57.6K bps 8

115.2K bps 4

230.4K bps 2

460.8K bps 1

Omega Engineering OMG-ULTRA COMM+2.PCI Page 8

Card Setup

Baud Rates and Divisors for the ‘Div2’ mode

The following table shows some common data rates and the rates you should
choose to match them if using the adapter in the ‘Div2’ mode.

For this Data Rate Choose this Data Rate

1200 bps 600 bps
2400 bps 1200 bps
4800 bps 2400bps
9600 bps 4800 bps

19.2K bps 9600 bps

38.4K bps 19.2K bps

57.6 K bps 28.8K bps

115.2 K bps 57.6 K bps

230.4 K bps 115.2 K bps

If your communications package allows the use of Baud rate divisors, choose the
appropriate divisor from the following table:

For this Data Rate Choose this Divisor

1200 bps 192
2400 bps 96
4800 bps 48
9600 bps 24

19.2K bps 12

38.4K bps 8

57.6K bps 4

115.2K bps 2

230.4K bps 1

Omega Engineering OMG-ULTRA COMM+2.PCI Page 9

Installation

Installation

Operating System Installation
DOS

Refer to the ‘PCI.txt’ file found in the \DOS\PCI sub-directory on the supplied
Serial Utilities Diskette.

Windows 3.1x

Refer to the Win3x.hlp file found in the \Windows\3.1x sub-directory on the
supplied Serial Utilities Diskette.

Windows 95

Refer to the PCI.hlp file found in the \Windows \95 sub-directory on the supplied
Serial Utilities Diskette.

Windows NT

Refer to the PCI.hlp file found in the \Windows \NT sub-directory on the supplied
Serial Utilities Diskette.

Hardware Installation

The OMG-ULTRA COMM+2.PCI can be installed in any of the PCI expansion
slots and contains several jumper straps for each port that must be set for proper
operation.

1. Turn off PC power. Disconnect the power cord.

2. Remove the PC case cover.

3. Locate an available PCI slot and remove the blank metal slot cover.

4. Gently insert the OMG-ULTRA COMM+2.PCI into the slot. Make sure that

the adapter is seated properly.

5. Replace the screw.

6. Replace the cover.

7. Connect the power cord.
Installation is complete.

Omega Engineering OMG-ULTRA COMM+2.PCI Page 10

Technical Description

Technical Description

The Omega Engineering OMG-ULTRA COMM+2.PCI provides a PCI interface
adapter with 2 asynchronous serial ports providing a versatile interface, field
selectable as RS-232 for modems, printers and plotters, as well as RS-422/485 for
industrial automation and control applications.

The OMG-ULTRA COMM+2.PCI utilizes the 16550 UART. This chip features
programmable baud rates, data format, interrupt control and a 16-byte input and
output FIFO. Also available as an option is the 16C650 UART that provides a
deeper FIFO (32 bytes) and enhanced clocking features.

Interrupts

A good description of an interrupt and it’s importance to the IBM PC can be
found in the book ‘Peter Norton’s Inside the PC, Premier Edition’:

“ One of the key things that makes a computer different from any other kind of
man-made machine is that computers have the capability to respond to the
unpredictable variety of work that comes to them. The key to this capability is a
feature known as interrupts. The interrupt feature enables the computer to
suspend whatever it is doing and switch to something else in response to an
interruption, such as the press of a key on the keyboard.”

A good analogy of a PC interrupt would be the phone ringing. The phone ‘bell’
is a request for us to stop what we are currently doing and take up another task
(speak to the person on the other end of the line). This is the same process the
PC uses to alert the CPU that a task must be preformed. The CPU upon receiving
an interrupt makes a record of what the processor was doing at the time and
stores this information on the ‘stack’; this allows the processor to resume its
predefined duties after the interrupt is handled, exactly where it left off. Every
main sub-system in the PC has it’s own interrupt, frequently called an IRQ (short
for Interrupt ReQuest). The following IRQ table will define the system IRQs as
well as show typically free IRQs.

In these early days of PC’s Omega Engineering decided that the ability to share
IRQs was an important feature for any add-in I/O card. Consider that in the IBM
XT the available IRQs were IRQ0 through IRQ7. Of these interrupts only IRQ2-5
and IRQ7 were actually available for use. This made the IRQ a very valuable
system resource. To make the maximum use of these system resources Omega
Engineering devised an IRQ sharing circuit that allowed more than one port to
use a selected IRQ. This worked fine as a hardware solution but presented the

Omega Engineering OMG-ULTRA COMM+2.PCI Page 11

Technical Description
software designer with a challenge to identify the source of the interrupt. The

software designer frequently used a technique referred to as ‘round robin
polling’. This method required the interrupt service routine to ‘poll’ or interrogate
each UART as to its interrupt pending status. This method of polling was
sufficient for use with slower speed communications, but as modems increased
their through put abilities this method of servicing shared IRQs became
inefficient.

Why use an ISP?

The answer to the polling inefficiency was the Interrupt Status Port (ISP). The
ISP is a read only 8-bit register that sets a corresponding bit when an interrupt is
pending. Port 1 interrupt line corresponds with Bit D0 of the status port, Port 2
with D1 etc. The use of this port means that the soft ware designer now only has
to poll a single port to determine if an interrupt is pending.

The ISP is at Base+7 on each port (Example: Base = 280 Hex, Status Port = 287,
28F… etc.). The OMG-ULTRA COMM+2.PCI will allow any one of the available
locations to be read to obtain the value in the status register. Both status ports
on the OMG-ULTRA COMM+2.PCI are identical, so any one can be read.
Example: This indicates that Channel 2 has an interrupt pending.

Bit Position: 7 6 5 4 3 2 1 0
Value Read: 0 0 0 0 0 0 1 0

Connector Pin Assignments
RS-232

Name Pin # Mode

TD Transmit Data 3 Output
RTS Request To Send 7 Output
DTR Data Term Ready 4 Output
GND Ground 5
RD Receive Data 2 Input
DCD Data Carrier Detect 1 Input
DSR Data Set Ready 6 Input
CTS Clear To Send 8 Input
RI Ring Indicator 9 Input

Note: These assignments meet EIA/TIA/ANSI-574 DTE for DB-9 type

connectors.

Omega Engineering OMG-ULTRA COMM+2.PCI Page 12

Technical Description

RS-422/485

Signal Name Pin # Mode

GND Ground 5
TX + Transmit Data Positive 4 Output
TX- Transmit Data Negative 3 Output
RTS+ Request To Send Positive 6 Output
RTS- Request To Send Negative 7 Output
RX+ Receive Data Positive 1 Input
RX- Receive Data Negative 2 Input
CTS+ Clear To Send Positive 9 Input
CTS- Clear To Send Negative 8 Input

Omega Engineering OMG-ULTRA COMM+2.PCI Page 13

Specifications

Specifications

Environmental Specifications

Specification Operating Storage

Temperature Range

Humidity Range 10 to 90% R.H.

Manufacturing .

• All Omega Engineering Printed Circuit boards are built to U. L. 94V0 rating

and are 100% electrically tested. These printed circuit boards are solder mask
over bare copper or solder mask over tin nickel.

Power Consumption

Supply line +12VDC -12VDC +5 VDC

Rating 50 mA 50 mA 480 mA

0º to 50º C

(32º to 122º F)

Non-Condensing

-20º to 70º C

(-4º to 158º F)

10 to 90% R.H.

Non-Condensing

Mean Time Between Failures (MTBF)

Greater than 150,000 hours. (Calculated)

Physical Dimensions

Board length 5.0 inches (12.7 cm)
Board Height including Goldfingers 4.2 inches (10.66 cm)
Board Height excluding Goldfingers 3.875 inches (9.841 cm)

Omega Engineering OMG-ULTRA COMM+2.PCI Page 14

Appendix A - Troubleshooting

Appendix A - Troubleshooting

A Serial Utility Diskette is supplied with the Omega Engineering adapter and will
be used in the troubleshooting procedures. By using this diskette and following
these simple steps, most common problems can be eliminated without the need to
call Technical Support.

1. Identify all I/O adapters currently installed in your system. This includes
your on-board serial ports, controller cards, sound cards etc. The I/O
addresses used by these adapters, as well as the IRQ (if any) should be
identified.

2. Configure your Omega Engineering adapter so that there is no conflict with
currently installed adapters. No two adapters can occupy the same I/O
address.

3. Make sure the Omega Engineering adapter is using a unique IRQ. While the
Omega Engineering adapter does allow the sharing of IRQs, many other
adapters (i.e. SCSI adapters & on-board serial ports) do not. The IRQ is
typically selected via an on-board header block. Refer to the section on Card
Setup for help in choosing an I/O address and IRQ.

4. Make sure the Omega Engineering adapter is securely installed in a
motherboard slot.

5. When running DOS, Windows 3.x or other operating systems refer to the
Serial Utilities Disk 1 and the User Manual to verify that the Omega
Engineering adapter is configure d correctly. The supplied software contains
a diagnostic program 'SSD' that runs under DOS and will verify if an adapter
is configured properly. This diagnostic program is written with the user in
mind and is easy to use. Refer to the README.txt file on the supplied
diskette for detailed instructions on using 'SSD'.

6. For Windows 95/98 and Windows NT, the diagnostic tool 'WinSSD' is
installed in the Omega folder on the Start Menu during the setup process.
First find the ports using the Device Manager, then use 'WinSSD' to verify
that the ports are functional.

Always use the Omega Engineering diagnostic software when troubleshooting a
problem. This will help eliminate any software issues and identify any hardware
conflicts

Omega Engineering OMG-ULTRA COMM+2.PCI Page 15

Appendix B - How To Get Assistance

Appendix B - How To Get Assistance

Please refer to Appendix A - Troubleshooting prior to calling Technical Support.

1. Read this manual thoroughly before attempting to install the
adapter in your system.

2. When calling for technical assistance, please have your user
manual and current adapter settings. If possible, please have the
adapter installed in a computer ready to run diagnostics.

RETURN AUTHORIZATION MUST BE OBTAINED FROM OMEGA
ENGINEERING BEFORE RETURNED MERCHANDISE WILL BE ACCEPTED.
AUTHORIZATION CAN BE OBTAINED BY CALLING OMEGA
ENGINEERING AND REQUESTING A RETURN MERCHANDISE
AUTHORIZATION (RMA) NUMBER.

Omega Engineering OMG-ULTRA COMM+2.PCI Page 16

Appendix C – Electrical Interface

Appendix C - Electrical Interface

RS-232

Quite possibly the most widely used communication standard is RS-232. This
implementation has been defined and revised several times and is often referred
to as RS-232 or EIA/TIA-232. The IBM PC computer defined the RS-232 port on a
9 pin D sub connector and subsequently the EIA/TIA approved this
implementation as the EIA/TIA-574 standard. This standard is defined as the

9-Position Non-Synchronous Interface between Data Terminal Equipment and
Data Circuit-Terminating Equipment Employing Serial Binary Data
Interchange. Both implementations are in wide spread use and will be referred to

as RS-232 in this document. RS-232 is capable of operating at data rates up to 20
Kbps at distances less than 50 ft. The absolute maximum data rate may vary due
to line conditions and cable lengths. RS-232 is a single ended or unbalanced
interface, meaning that a single electrical signal is compared to a common signal
(ground) to determine binary logic states. The RS-232 and the EIA/TIA-574
specification define two types of interface circuits, Data Terminal Equipment
(DTE) and Data Circuit-Terminating Equipment (DCE). The OMG-ULTRA

COMM+2.PCI is a DTE device.

RS-422

The RS-422 specification defines the electrical characteristics of balanced voltage
digital interface circuits. RS-422 is a differential interface that defines voltage
levels and driver/receiver electrical specifications. On a differential interface,
logic levels are defined by the difference in voltage between a pair of outputs or
inputs. In contrast, a single ended interface, for example RS-232, defines the logic
levels as the difference in voltage between a single signal and a common ground
connection. Differential interfaces are typically more immune to noise or voltage
spikes that may occur on the communication lines. Differential interfaces also
have greater drive capabilities that allow for longer cable lengths. RS-422 is rated
up to 10 Megabits per second and can have cabling 4000 feet long. RS-422 also
defines driver and receiver electrical characteristics that will allow 1 driver and up
to 32 receivers on the line at once. RS-422 signal levels range from 0 to +5 volts.
RS-422 does not define a physical connector.

Omega Engineering OMG-ULTRA COMM+2.PCI Page 17

Appendix C – Electrical Interface

RS-485

RS-485 is backwardly compatible with RS-422; however, it is optimized for
partyline or multi-drop applications. The output of the RS-422/485 driver is
capable of being Active (enabled) or Tri-State (disabled). This capability allows
multiple ports to be connected in a multi-drop bus and selectively polled. RS-485
allows cable lengths up to 4000 feet and data rates up to 10 Megabits per second.
The signal levels for RS-485 are the same as those def ined by RS-422. RS-485 has
electrical characteristics that allow for 32 drivers and 32 receivers to be
connected to one line. This interface is ideal for multi-drop or network
environments. RS-485 tri-state driver (not dual-state) will allow the electrical
presence of the driver to be removed from the line. Only one driver may be active
at a time and the other driver(s) must be tri-stated. RS-485 can be cabled in two
ways, two wire and four wire mode. Two wire mode does not allow for full duplex
communication, and requires that data be transferred in only one direction at a
time. For half-duplex operation, the two transmit pins should be connected to the
two receive pins (Tx+ to Rx+ and Tx- to Rx-). Four wire mode allows full duplex
data transfers. RS-485 does not define a connector pin -out or a set of modem
control signals. RS-485 does not define a physical connector.

Omega Engineering OMG-ULTRA COMM+2.PCI Page 18

Appendix D - Asynchronous Communications

Appendix D - Asynchronous Communications

Serial data communications implies that individual bits of a character are
transmitted consecutively to a receiver that assembles the bits back into a
character. Data rate, error checking, handshaking, and character framing
(start/stop bits) are pre-defined and must correspond at both the transmitting
and receiving ends.

Asynchronous communications is the standard means of serial data
communication for PC compatibles and PS/2 computers. The original PC was
equipped with a communication or COM: port that was designed around an 8250
Universal Asynchronous Receiver Transmitter (UART). This device allows
asynchronous serial data to be transferred through a simple and straightforward
programming interface. A start bit, followed by a pre -defined number of data bits
(5, 6, 7, or 8) defines character boundaries for asynchronous communications.
The end of the character is defined by the transmission of a pre -defined number
of stop bits (usual 1, 1.5 or 2). An extra bit used for error detection is often
appended before the stop bits.

Idle state of
line

1

0

5 to 8 Data Bits

Figure 11 - Asynchronous Communications Bit Diagram

Odd, Even
or
Unused

P
BIT

STOP

Remain Idle or
next start bit

1

1.5
2

This special bit is called the parity bit. Parity is a simple method of determining if
a data bit has been lost or corrupted during transmission. There are several
methods for implementing a parity check to guard against data corruption.
Common methods are called (E)ven Parity or (O)dd Parity. Sometimes parity is
not used to detect errors on the data stream. This is refereed to as (N)o parity.
Because each bit in asynchronous communications is sent consecutively, it is
easy to generalize asynchronous communications by stating that each character
is wrapped (framed) by pre -defined bits to mark the beginning and end of the
serial transmission of the character. The data rate and communication parameters
for asynchronous communications have to be the same at both the transmitting
and receiving ends. The communication parameters are baud rate, parity, number
of data bits per character, and stop bits (i.e. 9600,N,8,1).

Omega Engineering OMG-ULTRA COMM+2.PCI Page 19

Appendix E - Silk-Screen

Appendix E - Silk -Screen

5.0"

4.2"

Omega Engineering OMG-ULTRA COMM+2.PCI Page 20

Warranty

Appendix F - Compliance Notices

Federal Communications Commission Statement

FCC - This equipment has been tested and found to comply with the limits for
Class A digital device, pursuant to Part 15 of the FCC Rules. These limits are
designed to provide reasonable protection against harmful interference when the
equipment is operated in a commercial environment. This equipment generates,
uses, and can radiate radio frequency energy and, if not installed and used in
accordance with the instruction manual, may cause harmful interference to radio
communications. Operation of this equipment in a residential area is likely to
cause harmful interference in such case the user will be required to correct the
interference at his own expense.

EMC Directive Statement

Products bearing the CE Label fulfill the requirements of
the EMC directive (89/336/EEC) and of the low-voltage
directive (73/23/EEC) issued by the European Commission.
To obey these directives, the following European

standards must be met:

• EN55022 Class A - “Limits and methods of measurement of radio

interference characteristics of information technology equipment”

• EN50082-1 - “Electromagnetic compatibility - Generic immunity
standard” Part 1 : Residential, commercial and light industry

• EN60950 (IEC950) - “Safety of information technology
equipment, including electrical business equipment”

Warning
This is a Class A Product. In a domestic environment this product may cause
radio interference in which case the user may be required to take adequate
measures.

Always use cabling provided with this product if possible. If no cable is
provided or if an alternate cable is required, use high quality shielded cabling to
maintain compliance with FCC/EMC directives.

Omega Engineering OMG-ULTRA COMM+2.PCI Page 21

WARRANTY/DISCLAIMER

OMEGA ENGINEERING, INC. warrants this unit to be free of defects in materials and workmanship for a
period of 13 months from date of purchase. OMEGA’s WARRANTY adds an additional one (1) month
grace period to the normal one (1) year product warranty to cover handling and shipping time. This
ensures that OMEGA’s customers receive maximum coverage on each product.

If the unit malfunctions, it must be returned to the factory for evaluation. OMEGA’s Customer Service
Department will issue an Authorized Return (AR) number immediately upon phone or written request.
Upon examination by OMEGA, if the unit is found to be defective, it will be repaired or replaced at no
charge. OMEGA’sWARRANTY does not apply to defects resulting from any action of the purchaser, includ­ing but not limited to mishandling, improper interfacing, operation outside of design limits,
improper repair, or unauthorized modification. This WARRANTY is VOID if the unit shows evidence of
having been tampered with or shows evidence of having been damaged as a result of excessive corrosion;
or current, heat, moisture or vibration; improper specification; misapplication; misuse or other operating
conditions outside of OMEGA’s control. Components which wear are not warranted, including but not
limited to contact points, fuses, and triacs.

OMEGA is pleased to offer suggestions on the use of its various products. However,
OMEGA neither assumes responsibility for any omissions or errors nor assumes liability for any
damages that result from the use of its products in accordance with information provided by
OMEGA, either verbal or written. OMEGA warrants only that the parts manufactured by it will be
as specified and free of defects. OMEGA MAKES NO OTHER WARRANTIES OR
REPRESENTATIONS OF ANY KIND WHATSOEVER, EXPRESS OR IMPLIED, EXCEPT THAT OF TITLE,
AND ALL IMPLIED WARRANTIES INCLUDING ANY WARRANTY OF MERCHANTABILITY AND
FITNESS FOR A PARTICULAR PURPOSE ARE HEREBY DISCLAIMED. LIMITATION OF
LIABILITY: The remedies of purchaser set forth herein are exclusive, and the total liability of
OMEGA with respect to this order, whether based on contract, warranty, negligence,
indemnification, strict liability or otherwise, shall not exceed the purchase price of the
component upon which liability is based. In no event shall OMEGA be liable for
consequential, incidental or special damages.

CONDITIONS: Equipment sold by OMEGA is not intended to be used, nor shall it be used: (1) as a “Basic
Component” under 10 CFR 21 (NRC), used in or with any nuclear installation or activity; or (2) in medical
applications or used on humans. Should any Product(s) be used in or with any nuclear installation or
activity, medical application, used on humans, or misused in any way, OMEGA assumes no responsibility
as set forth in our basic WARRANTY/DISCLAIMER language, and, additionally, purchaser will indemnify
OMEGA and hold OMEGA harmless from any liability or damage whatsoever arising out of the use of the
Product(s) in suc h a manner.

RETURN REQUESTS/INQUIRIES

Direct all warranty and repair requests/inquiries to the OMEGA Customer Service Department. BEFORE
RETURNING ANY PRODUCT(S) TO OMEGA, PURCHASER MUST OBTAIN AN AUTHORIZED RETURN
(AR) NUMBER FROM OMEGA’S CUSTOMER SERVICE DEPARTMENT (IN ORDER TO AVOID
PROCESSING DELAYS). The assigned AR number should then be marked on the outside of the return
package and on any correspondence.

The purchaser is responsible for shipping charges, freight, insurance and proper packaging to prevent
breakage in transit.

FOR W

ARRANTY

RETURNS, please have the
following information available BEFORE
contacting OMEGA:

1. Purc hase Order number under which the product

was PURCHASED,

2. Model and serial number of the product under

warranty, and

3. Repair instructions and/or specific problems

relative to the product.

FOR NON-W

ARRANTY

REPAIRS,

consult OMEGA
for current repair charges. Have the following
information available BEFORE contacting OMEGA:

1. Purchase Order number to cover the COST

of the repair,

2. Model and serial number of the product, and

3. Repair instructions and/or specific problems

relative to the product.

OMEGA’s policy is to make running changes, not model changes, whenever an improvement is possible. This affords
our customers the latest in technology and engineering.

OMEGA is a registered trademark of OMEGA ENGINEERING, INC.
© Copyright 2002 OMEGA ENGINEERING, INC. All rights reserved. This document may not be copied, photocopied,

reproduced, translated, or reduced to any electronic medium or machine-readable form, in whole or in part, without the
prior written consent of OMEGA ENGINEERING, INC.

M3106/0303

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