CyberResearch COMHP 7404 User manual

®
Serial Communications
COMHP 7404/-D25
PCI 4-Port Serial Interface Card,
460.8 kbps Data Rate, 128-Byte
FIFO Buffer, with 4 DB-9M Cable
or 4 DB-25M Cable (-D25 Model)
USER’S MANUAL
VER. 2.0C• Jun-10
No part of this manual may be reproduced without permission
CyberResearch®,Inc.
Hwww.cyberresearch.com
25 Business Park Dr., Branford, CT 06405 USA
203-643-5000 (9 A.M. to 5 P.M. EST) FAX: [phone]

CyberResearch® Serial Communications COMHP 7404/-D25
©Copyright 2010
All Rights Reserved.
June 9, 2010
The information in this document is subject to change without prior notice in order
to improve reliability, design, and function and does not represent a commitment
on the part of CyberResearch, Inc.
In no event will CyberResearch, Inc. be liable for direct, indirect, special,
incidental, or consequential damages arising out of the use of or inability to use
the product or documentation, even if advised of the possibility of such damages.
This document contains proprietary information protected by copyright. All rights
are reserved. No part of this manual may be reproduced by any mechanical,
electronic, or other means in any form without prior written permission of
CyberResearch, Inc.
Trademarks
“CyberResearch,” and “COMHP 7404/-D25,” are trademarks of CyberResearch,
Inc. Other product names mentioned herein are used for identification purposes
only and may be trademarks and/or registered trademarks of their respective
companies.
• NOTICE •
CyberResearch, Inc. does not authorize any CyberResearch product for use in life
support systems, medical equipment, and/or medical devices without the written
approval of the President of CyberResearch, Inc. Life support devices and
systems are devices or systems which are intended for surgical implantation into
the body, or to support or sustain life and whose failure to perform can be
reasonably expected to result in injury. Other medical equipment includes devices
used for monitoring, data acquisition, modification, or notification purposes in
relation to life support, life sustaining, or vital statistic recording. CyberResearch
products are not designed with the components required, are not subject to the
testing required, and are not submitted to the certification required to ensure a
level of reliability appropriate for the treatment and diagnosis of humans.
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Revision History
Revision # Description Date of Issue
1.0 Initial Release May 1, 2007
2.0C Revision June 9, 2010
iv ©Copyright 2010 CyberResearch, Inc.

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Table of Contents
INTRODUCTION............................................................................................................................................1
OVERVIEW .....................................................................................................................................................................1
WHAT’S INCLUDED ........................................................................................................................................................1
FACTORY DEFAULT SETTINGS........................................................................................................................................1
CARD SETUP ................................................................................................................................................2
RS-485 ENABLE MODES ................................................................................................................................................2
Interface Mode Examples SW1 – SW4 (continued) ..................................................................................................4
ADDRESS AND IRQ SELECTION ......................................................................................................................................4
ELECTRICAL INTERFACE SELECTION..............................................................................................................................5
CLOCK MODES...............................................................................................................................................................6
BAUD RATES AND DIVISORS FOR THE ‘DIV1’ MODE......................................................................................................6
INSTALLATION.............................................................................................................................................7
OPERATING SYSTEM INSTALLATION ..............................................................................................................................7
For Windows Users....................................................................................................................................................7
Other Operating Systems............................................................................................................................................7
SYSTEM INSTALLATION..................................................................................................................................................7
TECHNICAL DESCRIPTION...........................................................................................................................8
CONNECTOR PIN ASSIGNMENTS.....................................................................................................................................8
RS-422/485 (DB 9 Male)........................................................................................................................................8
RS-232 (DB-9 Male) ..............................................................................................................................................8
CONNECTOR PIN ASSIGNMENTS.....................................................................................................................................9
RS-232, RS-422/485 (DB-37 Male).......................................................................................................................9
SPECIFICATIONS ........................................................................................................................................10
ENVIRONMENTAL SPECIFICATIONS...............................................................................................................................10
MANUFACTURING ........................................................................................................................................................10
POWER CONSUMPTION .................................................................................................................................................10
MEAN TIME BETWEEN FAILURES (MTBF)...................................................................................................................10
PHYSICAL DIMENSIONS................................................................................................................................................10
APPENDIX A-TROUBLESHOOTING...........................................................................................................11
APPENDIX B-ELECTRICAL INTERFACE...................................................................................................12
RS-232.........................................................................................................................................................................12
RS-422.........................................................................................................................................................................12
RS-485.........................................................................................................................................................................13
APPENDIX C- ASYNCHRONOUS COMMUNICATIONS.................................................................................14
APPENDIX D-SILK-SCREEN .....................................................................................................................15
APPENDIX E-COMPLIANCE NOTICES......................................................................................................16
FEDERAL COMMUNICATIONS COMMISSION STATEMENT..............................................................................................16
EMC DIRECTIVE STATEMENT ......................................................................................................................................16

COMHP 7404/-D25 CyberResearch® Serial Communications
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TABLE OF FIGURES
Figure 1- Switches SW1- SW4, RS-422..................................................................................................................................3
Figure 2 - Switches SW1- SW4, RS-485 ‘Auto’ Enabled, with ‘No Echo’ and the termination resistor in circuit.........3
Figure 3 - Switches SW1- SW4, RS-485 ‘Auto’ Enabled, with ‘Echo’ and no termination resistor in circuit................3
Figure 4 - Switches SW1- SW4, RS-485 ‘RTS’ Enabled, with ‘No Echo’ and no termination resistor in circuit. .........4
Figure 5 - Switches SW1- SW4, RS-485 ‘RTS’ Enabled, with ‘Echo’ and no termination resistor in circuit. ...............4
Figure 6 - Asynchronous Communications Bit Diagram...................................................................................................14

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Introduction
Overview
The CyberResearch®COMHP 7404 is a four channel RS-232/485/422 PCI Bus serial I/O adapter supporting data rates up to
460.8K bps.
The RS-232 compatibility allows for connection to devices utilizing the RS-232 electrical interface, such as modems,
data-entry terminals, and plotters.
RS-422 provides excellent communications for long distance device connections up to 4000ft., where noise immunity and
high data integrity are essential.
RS-485 is optimized for ‘Multi-Drop’ or ‘Party-line’ operations selecting data from multiple peripherals (as many as 31
devices can be connected on an RS-485 bus).
In both RS-485 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.
A quadracable splits the DB-37 connector on the backplate of the CyberResearch Adapter into four separate cables. On the
COMHP 7404, these four cables terminate in DB-9M connectors. On the COMHP 7404-D25, these four cables terminate in
DB-25M connectors.
What’s Included
The COMHP 7404 is shipped with the following items. If any of these items is missing or damaged, contact CyberResearch,
Inc.
•COMHP 7404 Serial I/O Adapter
•SeaCOM Software
•Quadracable Cable providing 4 DB-9 connectors (COMHP 7404)
•Quadracable Cable providing 4 DB-25 connectors (COMHP 7404-D25)
Factory Default Settings
The COMHP 7404 factory default settings are as follows:
Port # Clock DIV Mode Enable Mode
Port 1 4 RS-422
Port 2 4 RS-422
Port 3 4 RS-422
Port 4 4 RS-422
To install the COMHP 7404 using factory default settings, refer to Installation on page 7.

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Card Setup
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 COMHP 7404 is the ability to be RS-485 compatible without the need for special software
or drivers. This ability is especially useful in Windows and other protected mode environments where the lower level I/O
control is abstracted from the application program. This ability means that the user can effectively use the COMHP 7404 in
an RS-485 application with existing (i.e. standard RS-232) software drivers.
Switches SW1 - SW4 are used to control the RS-485 mode functions for the driver circuit. The selections are ‘RTS’ enable
(silk-screen ‘RT’) or ‘Auto’ enable (silk-screen ‘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 these switches 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’.
Typically, each end of the RS-485 bus must have a line-terminating resistor (RS-422 terminates the receive end only). A
120-ohm resistor is across each RS-422/485 input in addition to a 1K-ohm pull-up/pull-down combination that biases the
receiver inputs. Only the ends of an RS-485 network should have the 120-Ohm terminating resistor. Position 4 (silk-screen
‘T’) selects the presence of the 120-Ohm termination resistor across the input data pins (RX+/RX-). To add the termination
select the ‘On’ position, to remove it select the ‘Off’ position.
For RS-422/530/449 compatibility set all switches ‘Off’. Examples on the following pages describe some of the valid
settings for SW1-SW4.

CyberResearch® Serial Communications COMHP 7404/-D25
Interface Mode Examples SW1 – SW4
1 2 3 4
ON
OFF
AT RT NE T
Figure 1- Switches SW1- SW4, RS-422
1 2 3 4
ON
OFF
AT RT NE T
Figure 2 - Switches SW1- SW4, RS-485 ‘Auto’ Enabled, with ‘No Echo’ and the termination resistor in circuit.
1 2 3 4
ON
OFF
AT RT NE T
Figure 3 - Switches SW1- SW4, RS-485 ‘Auto’ Enabled, with ‘Echo’ and no termination resistor in circuit.
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COMHP 7404/-D25 CyberResearch® Serial Communications
Interface Mode Examples SW1 – SW4 (continued)
1 2 3 4
ON
OFF
AT RT NE T
Figure 4 - Switches SW1- SW4, RS-485 ‘RTS’ Enabled, with ‘No Echo’ and no termination resistor in circuit.
1 2 3 4
ON
OFF
AT RT NE T
Figure 5 - Switches SW1- SW4, RS-485 ‘RTS’ Enabled, with ‘Echo’ and no termination resistor in circuit.
Address and IRQ selection
The COMHP 7404 is automatically assigned resources by your motherboard BIOS. Only the I/O addresses may be modified
by the user. Adding or removing other hardware may change the assignment of I/O addresses and IRQs.
4©Copyright 2010 CyberResearch, Inc.

CyberResearch® Serial Communications COMHP 7404/-D25
Electrical Interface Selection
Each port on the COMHP 7404 has the ability to be used in either RS-232 or RS-422/485. This is selectable via eight 24 pin
DIP-shunts at E1-E8. Please use the following illustration to aid in the configuration of your electrical interface.
E5
E6
Port 2
RS-232 RS-422
E7
E8
Port 1
RS-232 RS-422
RS-422/485
E1
E2
Port 4
RS-232 RS-422
E3
E4
Port 3
RS-232 RS-422
RS-232
E5
E6
Port 2
RS-232 RS-422
E7
E8
Port 1
RS-232 RS-422
E1
E2
Port 4
RS-232 RS-422
E3
E4
Port 3
RS-232 RS-422
Figure 6 - Headers E1 - E4, Electrical Interface Selection
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COMHP 7404/-D25 CyberResearch® Serial Communications
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Clock Modes
The COMHP 7404 employs a unique clocking option that allows the end user to select from divide by 4, and divide by 1
clocking modes. These modes are selected at Header J1.
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 D4).
To select the Baud rates above 115.2K select the divide by 1 mode (silk-screen D1).
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

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Installation
Operating System Installation
For Windows Users
Start by choosing Install Software at the beginning of the CD. Choose Asynchronous COM: Port Software, SeaCOM.
Other Operating Systems
Refer to the appropriate section of the Serial Utilities Software.
System Installation
The COMHP 7404 can be installed in any of the PCI expansion slots and contains configuration options 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 COMHP 7404 into the slot. Make sure that the adapter is seated properly.
5. Replace the screw.
6. Replace the cover.
7. Install the Cable
8. Connect the power cord.
Installation is complete.

COMHP 7404/-D25 CyberResearch® Serial Communications
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Technical Description
The CyberResearch®COMHP 7404 provides a PCI interface adapter with 4 RS-232/422/485 asynchronous serial ports for
industrial automation and control applications.
The COMHP 7404 utilizes the 16C864 UART. This chip features programmable baud rates, data format, interrupt control
and industry leading 128-byte transmit and receive FIFOs.
Connector Pin Assignments
RS-422/485 (DB 9 Male)
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
RS-232 (DB-9 Male)
Signal Name Pin # Mode
GND Ground 5
TD Transmit Data 3 Output
RTS Request To Send 7 Output
DTR Data Terminal Ready 4 Output
RD Receive Data 2 Input
CTS Clear To Send 8 Input
DSR Data Set Ready 6 Input
DCD Data Carrier Detect 1 Input
RI Ring Indicator 9 Input
Technical Note: Please terminate any control signals that are not going to be used. The most common way to do this is
connect RTS to CTS and RI. Also, connect DCD to DTR and DSR. Terminating these pins, if not used, will help ensure you
get the best performance from your adapter.

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Connector Pin Assignments
RS-232, RS-422/485 (DB-37 Male)
Port # 1 2 3 4
RS-422/485 RS-232
RX+ DCD 37 10 28 1
RX- RD 36 11 27 2
TX- TD 35 12 26 3
TX+ DTR 34 13 25 4
GND GND 33 14 24 5
RTS+ DSR 18 29 9 20
RTS- RTS 17 30 8 21
CTS- CTS 16 31 7 22
CTS+ RI 15 32 6 23
Technical Note: Board connector is a DB-37M. Mating connector is a DB-37S, ACON P/N: D-37SK-SFS-T or equivalent.

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Specifications
Environmental Specifications
Specification Operating Storage
Temperature
Range 0º to 50º C
(32º to 122º F) -20º to 70º C (-4º to 158º F)
Humidity Range 10 to 90% R.H.
Non-Condensing 10 to 90% R.H. Non-Condensing
Manufacturing
•All Systems 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 +12 VDC -12 VDC +5 VDC
Rating 60 mA 100 mA 620 mA
Mean Time Between Failures (MTBF)
Greater than 150,000 hours. (Calculated)
Physical Dimensions
Board length 6.5 inches (16.51 cm)
Board Height including Goldfingers 4.2 inches (10.66 cm)
Board Height excluding Goldfingers 3.875 inches (9.841 cm)

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Appendix A - Troubleshooting
SeaCOM Software is supplied with the CyberResearch adapter and will be used in the troubleshooting procedures. By using
this software 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 CyberResearch 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 CyberResearch adapter is using a unique IRQ. While the CyberResearch 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 CyberResearch adapter is securely installed in a motherboard slot.
5. When running DOS or Windows 3.x refer to the supplied SeaCOM software and this User Manual to verify that the
CyberResearch adapter is configured correctly. This software contains a diagnostic program ‘SSD’ that will verify if an
adapter is configured properly. This diagnostic program is written with the user in mind and is easy to use.
6. For Windows 95/98/ME/NT/2000, the diagnostic tool ‘WinSSD’ is installed in the SeaCOM 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.
7. Always use the diagnostic software when troubleshooting a problem. This will eliminate any software issues from the
equation.

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Appendix B - 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-C/D/E or EIA/TIA-232-C/D/E. It is defined as “Interface between Data
Terminal Equipment and Data Circuit- Terminating Equipment Employing Serial Binary Data Interchange”. The
mechanical implementation of RS-232 is on a 25-pin D sub connector. 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 has 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 20K bps / 50 ft. The absolute
maximum data rate may vary due to line conditions and cable lengths. RS-232 often operates at 38.4K bps over very short
distances. The voltage levels defined by RS-232 range from -12 to +12 volts. 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. A
voltage of +12 volts (usually +3 to +10 volts) represents a binary 0 (space) and -12 volts (-3 to -10 volts) denote a binary 1
(mark). 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 Adapter is a DTE interface.
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.

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RS-485
RS-485 is backwardly compatible with RS-422; however, it is optimized for party line 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 defined 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.

COMHP 7404/-D25 CyberResearch® Serial Communications
Appendix C- 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 (usually 1, 1.5 or 2). An extra bit used for error detection is often appended before the stop bits.
Remain Idle o
r
next start bit
Odd, Even
or
Unused
STOP
P
BIT
5 to 8 Data Bits
Idle state of
line
1
0
1
1.5
2
Figure 7 - Asynchronous Communications Bit Diagram
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).
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