ICS Advent PCI-COM485/8 User manual

Model PCI-COM485/8
Product Manual
MANUAL NUMBER : 00650-146-1B

Page - iii
FOREWORD
This product manual provides information to install, operate and or program the referenced product(s)
manufactured or distributed by ICS Advent. The following pages contain information regarding the
warranty and repair policies.
Check our Web site (www.icsadvent.com) for technical information, manuals, and BIOS updates.
Technical assistance is also available at: 800-480-0044 (U.S.) or 858-677-0877 (international).
Customer Comments: If you experience any problems with this manual or just want to provide some
feedback, please send us a message using the online "Service Form" on our Web site (www.icsadvent.com)
under "Support." Detail any errors you find. We will correct the errors or problems as soon as possible and
post the revised manual in our online Support Library. Thank you.
The information in this document is provided for reference only. ICSAdvent does not assume any liability
arising from the application or use of the information or products described herein. This document may
contain or reference information and products protected by copyrights or patents and does not convey any
license under the patent rights of ICS Advent, nor the rights of others.
Copyright © 1998, a California Corporation, 6260 Sequence Drive, San Diego, CA92121-4371. ICSAdvent
is a Registered Trademark of ICS Advent. All trademarks and registered trademarks are the property of
their respective owners. All rights reserved. Printed in the United States of America. No part of this publi-
cation may be reproduced, stored in a retrieval system, or transmitted, in any form or by any means, elec-
tronic, mechanical, photocopying, recording , or otherwise, without the prior written permission of the pub-
lisher.

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Page - v
Shipments not in compliance with this Guarantee
and Limited Warranty Return Policy will not be ac-
cepted by ICS Advent.
Guarantee
A thirty day money-back guarantee is provided on all standard products sold. Special order products are
covered by our Limited Warranty, however they may not be returned for refund or credit. EPROMs,
RAM, Flash EPROMs or other forms of solid electronic media are not returnable for credit - but for
replacement only. Extended Warranty available. Consult factory.
Refunds
In order to receive a refund on a product for the purchase price, the product must not have been
damaged by the customer or by the common carrier chosen by the customer to return the goods and
the product must be returned complete (meaning all manuals, software, cables, etc.) within 30 days of
receipt and in an as-new and resalable condition. The Return Proceduremust be followed to assure
prompt refund.
Restocking Charges
Product returned after 30 days, and before 60 days, of the purchase will be subject to a minimum20%
restocking charge and charges for any damaged or missing parts. Products not returned within 60
days of purchase, or products which are not in an as-new and re-saleable condition, are not eligible
for credit return and will be returned to the customer.
Limited Warranty
Effective April 1, 1998, all products carry a 2-year limited warranty. Within two years of purchase,
ICS Advent will repair or replace, at our option, any defective product. ICS Advent will service the
warranty for all standard catalog products for the first two years from the date of shipment.
Please note: The 2-year warranty may not apply to special promotion items. Please consult the factory for
warranty verification.
The limited warranty is void if the product has been subjected to alteration, neglect, misuse, or abuse; if any
repairs have been attempted by anyone other than ICS Advent or its authorized agent; or if the failure is
caused by accident, acts of God, or other causes beyond the control of ICS Advent or the manufacturer.
Neglect, misuse, and abuse shall include any installation, operation, or maintenance of the product other than
in accordance with the user’s manual.
No agent, dealer, distributor, service company, or other party is authorized to change, modify, or extend the
terms of this Limited Warranty in any manner whatsoever. ICS Advent reserves the right to make changes
or improvements in any product without incurring any obligation to similarly alter products previously
purchased.

Page - vi
Return Procedure
For any Guarantee or Limited Warranty return, please contact ICS Advent's Customer Service at
800-480-0044 (U.S.) or 858-677-0877 (international) and obtain a Return Material Authorization (RMA)
Number. All product(s) returned to ICS Advent for service or credit must be accompanied by a Return
MaterialAuthorization (RMA) Number. Freight on all returned itemsmust be prepaid by the customer who
is responsible for any loss or damage caused by common carrier in transit. Returns for Warranty must
include a Failure Report for each unit, by serial number(s), as well as a copy of the original invoice showing
date of purchase.
To reduce risk of damage, returns of product must be in an ICS Advent shipping container. If the original
container has been lost or damaged, new shipping containers may be obtained from ICS Advent Customer
Service at a nominal cost.
ICS Advent owns all parts removed from repaired products. ICS Advent uses new and reconditioned parts
made by various manufacturers in performing warranty repairs and building replacement products.
If ICS Advent repairs or replaces a product, its warranty term is not extended.
ICSAdvent will normally return your replacement or repaired items via Second DayAir. Overnight delivery
or delivery via other carriers is available at an additional charge.
Limitation of Liability
In no event shall ICS Advent be liable for any defect in hardware, software, loss, or inadequacy of data of
any kind, or for any direct, indirect, incidental, or consequential damages in connection with or arising out of
the performance or use of any product furnished hereunder. ICSAdvent liability shall in no event exceed the
purchase price of the product purchased hereunder. The foregoing limitation of liability shall be equally
applicable to any service provided by ICSAdvent or its authorized agent.
Some Sales Items and Customized Systems are not subject to the guarantee and limited warranty.
However in these instances , any deviations will be disclosed prior to sales and noted in the original invoice.
ICS Advent reserves the right to refuse returns or credits on software or special order items.

Page - vii
Advisories
Three types of advisories are used throughout the manual to stress important points or warn of potential
hazards to the user or the system. They are the Note, the Caution, and theWarning. Following is an example
of each type of advisory:
Note: The note is used to present special instruction, or to provide extra information which may
help to simplify the use of the product.
CAUTION!
A Caution is used to alert you to a situation which if ignored may cause injury or
damage equipment.
WARNING!
AWarningisusedtoalertyouofasituationwhichifignoredwillcauseseriousinjury.
Cautions and Warnings are accented with triangular symbols. The exclamation symbol is used in all cautions
and warnings to help alert you to the important instructions. The lightning flash symbol is used on the left
hand side of a caution or a warning if the advisory relates to the presence of voltage which may be of
sufficient magnitude to cause electrical shock.
Use caution when servicing any electrical component. We have tried to identify the areas which may pose
a Caution or Warning condition in this manual; however, ICS Advent does not claim to have covered all
situations which might require the use of a Caution or Warning.
You must refer to the documentation for any component you install into a computer system to ensure proper
precautions and procedures are followed.

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Page - ix
Table of Contents
FOREWORD.............................................................................................. iii
Guarantee................................................................................................. iv
Limited Warranty ..................................................................................... iv
Return Procedure..................................................................................... v
Limitation of Liability................................................................................ v
Advisories ................................................................................................ vi
Chapter 1: Installation .................................................................................................. 1
Backing Up The Disk ............................................................................................................................ 1
HardDiskInstallation............................................................................................................................ 1
InstallingThe Card ................................................................................................................................4
WindowsNT 4.0Installation Instructionsfor thePCI-COM485/8 .................................................... 4
Interrupts........................................................................................................................................ 5
Input/OutputConnections............................................................................................................... 6
Chapter 2: Functional Description.............................................................................. 8
RS-485BalancedMode Operation ................................................................................................. 8
CommPort Compatibility ............................................................................................................... 8
CommunicationMode .................................................................................................................... 8
BaudRateRanges ......................................................................................................................... 9
Auto-RTSTransceiver Control ........................................................................................................ 9
Chapter 3: Option Selection ......................................................................................10
Terminations .................................................................................................................................10
Data Cable Wiring .........................................................................................................................10
BaudRateRanges ........................................................................................................................11
Chapter 4: Address Selection.................................................................................... 12
Chapter 5: Programming ...........................................................................................13
Sample Programs ................................................................................................................................13
RS-485Programming .......................................................................................................13
Initialization ......................................................................................................................13
Reception .....................................................................................................................................15
Transmission ................................................................................................................................16
Chapter 6: Specification ............................................................................................17
CommunicationsInterface.............................................................................................................17
Environmental ...............................................................................................................................17

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List of Figures
Figure2-1: PCI-COM485/8BLOCKDIAGRAM ........................................................................................... 9
Figure3-1: PCI-COM485/8Option Selection Map......................................................................................11
List of Tables
Table1-1: PinConnections......................................................................................................................... 7
Table5-1: BaudRate Divisor Values ..........................................................................................................14
Current Revision 1B
December 2000

Manual Number: 00650-146-1 Page 1
Chapter 1: Installation
Backing Up The Disk
The software supplied with the PCI-COM485/8 is provided on two 3.5-inch diskettes. As with any
software package, you should make back-up copies for everyday use and place your original master
diskettes in a safe location.
The easiest way to make a back-up copy is to use the DOS DISKCOPY utility.
In a single-drive system, the command is diskcopy a: a: [Enter]
In a windowed environment (such as OS2,Windows 3.1,Windows95, or WindowsNT) select all of
the files on the diskette and drag them to a backup destination.
Hard Disk Installation
The files contained on the master diskette must be installed onto your hard disk prior to use. To do
this, perform the following:
1.) Place the master diskette into the A: drive (substitute B: as appropriate).
2.) Change the active drive to A: by typing a: [Enter]
3.) Type install [Enter] and follow the on-screen prompts.
The installation process will create several directories on your hard disk. If you accept the installa-
tion defaults, the following structure will exist.
From the diskette titled “PCI-COM8S”
PCICOM4S: Root or base directory containing the SETUP.EXE setup program
used to help you configure jumpers and options on the card.
PSAMPLES: A subdirectory of PCICOM8S that contains Pascal samples.
CSAMPLES: A subdirectory of PCICOM8S that contains “C” samples.
BSAMPLES: AsubdirectoryofPCICOM8SthatcontainsQuickBASICsamples.
Contents of the Tools/Utilities Diskette
Bold indicates directory name.
VBACCES Sixteen-bit DLL drivers for use with VisualBASIC 3.0 and Windows 3.1 only.
These drivers provide four functions, similar to the ACCES32 DLL. However,
this DLL is only compatible with 16-bit executables. Migration from 16-bit to 32-
bit is simplified because of the similarity between VBACCES and ACCES32.

Manual Number: 00650-146-1Page 2
PCI-COM485/8Manual
ACCES95 and ACCESNT
These two drivers are mentioned for users migrating from older
versions of Tools. The functionality of ACCES95 and ACCESNT
has been combined into ACCES32.DLL, which is described be
low.
In order to modify your software to use the new ACCES32.DLL
instead of the older code, change the file you link to from ACCES95
or ACCESNT to ACCES32. No other changes are necessary.
To avoid recombining software that was written for ACCES95 or
ACCESNT, rename ACCES32.DLL to the appropriate name (95
or NT specific).
ACCES32 This directory contains the Windows 95/98/NT driver used to provide ac
cess to the hardware registers when writing 32-bit Windows software.
Several samples are provided in a variety of languages to demonstrate
how to use this driver. The DLL provides four functions (InPortB,
OutPortB, InPort, and OutPort) to access the hardware.
This directory also contains the device driver and install program for NT.
This device driver provides register-level hardware access from Windows
NT, normally called through ACCES32.DLL. Two methods of using the
driver are provided, the ACCES32.DLL (recommended) and the
DeviceIOControl handles direct to the SYS file (slightly faster)
ACCESNT.EXE Run this program on Windows NT to prepare ACCES32.DLL for use.
This is the install program for the SYS file itself. The ACCESNT.SYS
file must reside in the same directory as this executable, and is copied to
the drivers directory of NT. The driver is then dynamically started, and
can be used immediately. ACCESNT.EXE need be run only once per
computer. Once the driver is started, the registry entries tell WindowsNT
to load the driver on each boot-up.
No installation is necessary for Windows 95/98.
DLL Samples for using ACCES32.DLL are provided in this directory. Using
this DLL not only makes the hardware programming easier (MUCH easier),
but also one source file can be used for both Windows 95/98 and
WindowsNT. One executable can run under both operating systems and
still have full access to the hardware registers. The DLL is used exactly
like any other DLL, so it is compatible with any language capable of using
32-bit DLLs. Consult the manuals provided with your language’s com
piler for information on using DLLs in your specific environment.
SYS The samples in this directory are provided ONLY for WindowsNT. The
DeviceIOControl based interaction with the register-level driver is only
available in NT. If your code is written to use this method, it will not work
with Windows 95 or Windows 98.

Manual Number: 00650-146-1 Page 3
The SYS file is the actual workhorse behind hardware access in
WindowsNT. It is installed by ACCESNT.EXE and utilizes the
DeviceIOControl API function for interaction with user code. Samples
are provided demonstrating this API call, but it is strongly recommended
that the DLL interface be used. The DLL described above encapsulates
the SYS file and performs the DeviceIOControl calls at a small penalty in
speed. (A call through the DLL interface)
INSTALL.SRC Source code for ACCESNT.EXE is provided herein to allow you to write
OEM versions of the program or to integrate its functionality into your
own code.
PCI This directory contains PCI-bus specific programs and information. If
you are not using a PCI card, you can ignore or delete this directory.
PCIFind A utility for DOS and 16-bit Windows to determine PCI bus resources
allocated to installed PCI cards. Use this utility to find what base address
and IRQ your cards are installed at on the PCI bus. Use the files in the
PCI32 directory when running in Windows95/98/NT to perform the same
task.
BIOS A utility program is provided with source code you can use to determine
allocated resources at run-time from your own DOS and Windows 95 pro-
grams.
PCI32 This program is used to determine the base address and IRQ of installed
PCI cards in Windows 95/98 and NT. Run this program to both install and
use NtioPCI.SYS or PCIFind.DLL. This program modifies the registry by
adding a registry key describing the hardware that was detected. For in
formation about the format of the registry key, consult the card-specific
samples provided with the hardware. In Windows NT, NTioPCI.SYS runs
each time the computer is booted, thereby refreshing the registry as PCI
hardware is added or removed. In Windows 95/98, PCI32.EXE places
itself in the boot-sequence of the OS to refresh the registry on each power-
up.
This program used to be known as PCINT.EXE, but now supports both
Windows 95/98 and Windows NT.
Findbase.exe DOS utility to determine an available base address for ISA bus , non-PnP
cards. Run this program once, before the hardware is installed in the com
puter, to determine an available address to give the card. Once the address
has been determined, run the setup program provided with the hardware to
see instructions on setting the address switch and various option selec
tions.
Poly.exe A generic utility to convert a table of data into an nth order polynomial.
Useful for calculating linearization polynomial coefficients for thermo
couples and other non-linear sensors.
Risc.bat Abatch file demonstrating the command line parameters of RISCTerm.exe.

Manual Number: 00650-146-1Page 4
PCI-COM485/8Manual
RISCTerm.exe A dumb-terminal type communication program designed for RS422/485
operation. Used primarily with Remote data acquisition Pods and our
RS422/485 serial communication product line. Can be used to say hello to
an installed modem. RISCTerm stands for Really Incredibly Simple Com-
munications TERMinal.
Installing The Card
The PCI-COM485/8 card can be installed in a five-volt PCI slot of an IBM or compatible com-
puter. Before installing the card, carefully read the Option Selection section of this manual and
configure the card according to your requirements. Finally, our SETUP.EXE program will lead you
through the process of setting the options on the PCI-COM485/8. The setup program does not set
the options. These must be set manually by jumpers on the card.
To install the card:
1. Turn OFF computer power.
2. Remove the computer cover.
3. Install jumpers from either the Option Selection section of this manual or the suggestions of
our SETUP.EXE software program.
4. Install the card in an available PCI-bus slot.
5. Replace the computer cover and turn the computer ON.
6. Enter the CMOS setup program of your system and verify that the PCI plug-and-play option
is set appropriately for your system. Systems running Windows95 (or any other PNP-
compliant Operating System) should set the CMOS option to OS. Systems running under
DOS, WindowsNT 3.51, Windows 3.1, or any other non-PNP-compliant Operating System
should set the PNP CMOS option to BIOS or Motherboard. Save the option and continue
booting the system.
A “spider” cable is provided to interface between the 50-pin SCSI connector on the card, and your
system cabling. Eight individual 9-pin connectors are provided.
If you are using Windows95, your operating system should detect the new hardware and prompt
you for the installation disk. The simplest option is to insert the provided diskette into the A drive
and allow the operating system to look for the files that it wants.
The base address assigned by BIOS or the operating system can change each time new hardware is
installed into or removed from the computer.
PCI cards are assigned resources by the system. To determine the resource assigned, run
PCIFind(DOS/Win 3.1), PCINT(Win95/98/NT), or look in the operating systems list of Detected
Devices. In Win95/98/NT, this is the Device Manager of the system applet, found in the control
panel. See the Tools diskette for more information on PCIFind and PCINT.

Manual Number: 00650-146-1 Page 5
Windows NT 4.0 Installation Instructions for the PCI-COM485/8
Unlike Windows95, NT is not a plug-and-play compliant Operating System. Windows NTwill not
auto-detect and install new hardware devices. Therefore, in order to tell Windows NT that you
have installed eight new COM ports, you must use the utilities provided by NT in the Control
Panel.
Once you have installed the card in the computer and the system is booted to Windows NT 4.0
(Service Pack 3 or higher is recommended), you will also need to install several provided drivers
and utilities. These utilities are designed to detect the location of the hardware and report the base
address and IRQ assignments for your use. The TOOLS diskette contains these programs.
Place the TOOLS disk in a floppy drive (ex: A:), click the Start Menu, select the Run menu item,
and type A:INSTALL [enter]. This will run the installation program from the floppy disk to install
the software to your hard-disk.
Once the software installation is complete, use Explorer or My Computer to find the install direc-
tory, and enter the PCINT subdirectory. Double-click to run the PCINT.EXE program. This pro-
gram copies NTIOPCI.SYS to the [NT]\SYSTEM32\DRIVERS directory and dynamically loads
and runs the driver.
Note: If you previously installed an older version of NTIOPCI.SYS, please delete the file from
your [NT]\SYSTEM32\DRIVERS directory prior to running PCINT.EXE.
PCINT displays the list of COM addresses and the IRQ assigned. While this list is on screen, open
the CONTROL PANEL (START|RUN|CONTROL, START|SETTINGS|CONTROL PANEL, or
MY COMPUTER|CONTROL PANEL) and execute the PORTS applet.
Click Add...; a dialog box titled “Advanced Settings for New Port” will appear. Select the COM
port number of an available COM port, type the Base I/O Port Address of COMA and the IRQ from
the PCINT screen. Click OK.
You have now installed one port in NT. Continue Clicking Add... and selecting addresses for the
remainder of the eight ports.
All these steps are performed manually, but could be automated, by making registry entries in
various registry keys. Consult your Microsoft provided documentation for more information.
The base addresses and IRQ of the PCI-COM-8S is provided in the registry under the NTIOPCI
key, in a structure of type PCI_COMMON_CONFIG. See the sample program PCICOM for a
demonstration of how to read this structure and extract the addresses in an application program.

Manual Number: 00650-146-1Page 6
PCI-COM485/8Manual
Interrupts
Please note that, in WindowsNT, changes must be made to the system registry to support IRQ
sharing. The following is excerpted from “Controlling Multiport Serial I/O Cards” provided by
Microsoft in the MSDN library, documentid:mk:@ivt:nt40res/D15/S55FC.HTM, also available in
the WindowsNT Resource Kit.
The Microsoft serial driver can be used to control many dumb multiport serial cards. Dumb indi-
cates that the control includes no on-board processor. Each port of a multiport card has a separate
subkey under the HKLM\CurrentControlSet\Services\Serial subkey in the registry. In each of these
subkeys, you must add values for DosDevices, Interrupt, InterruptStatus, PortAddress, and
PortIndex because these are not detected by the Hardware Recognizer. (For descriptions and ranges
for these values, see Regentry.hlp, the Registry help file on the WindowsNT Workstation Resource
Kit CD.)
For example, if you have an eight-port PCI-COM485/8 card configured to use address 0xFC00
with an interrupt of 05, the values in the Registry are:
Serial2 subkey: Serial6 subkey:
PortAddress = REG_DWORD 0xFC00 PortAddress = REG_DWORD 0xFC20
Interrupt = REG_WORD 5 Interrupt = REG_DWORD 5
DosDevices = REG_SZ COM5 DosDevices = REG_SZ COM9
InterruptStatus = REG_DWORD 0xFC40 InterruptStatus=REG_DWORD0xFC40
PortIndex = REG_DWORD 1 PortIndex - REG_DWORD 5
Serial3 subkey: Serial7 subkey:
PortAddress = REG_DWORD 0xFC08 PortAddress = REG_DWORD 0xFC28
Interrupt = REG_DWORD 5 Interrupt = REG_DWORD 5
DosDevices = REG_SZ COM6 DosDevices = REG_SZ COM10
InterruptStatus = REG_DWORD 0xFC40 InterruptStatus=REG_DWORD0xFC40
PortIndex = REG_DWORD 2 PortIndex = REG_DWORD 6
Serial4 subkey: Serial8 subkey:
PortAddress =_DWORD 0xFC10 PortAddress = REG_DWORD 0xFC30
Interrupt = REG_DWORD 5 Interrupt = REG_DWORD 5
DosDevices = REG_SZ COM7 DosDevices = REG_SZ COM11
InterruptStatus = REG_DWORD 0xFC40 InterruptStatus=REG_DWORD0xFC40
PortIndex - REG_DWORD 3 PortIndex = REG_DWORD 7
Serial5 subkey: Serial9 subkey:
PortAddress = REG_DWORD 0xFC18 PortAddress = REG_DWORD 0xFC38
Interrupt = REG_DWORD 5 Interrupt = REG_DWORD 5
Dos Devices = REG_SZ COM8 DosDevices = REG_SZ COM12
InterruptStatus = REG_DWORD 0xFC40 InterruptStatus=REG_DWORD0xFC40
PortIndex = REG_DWORD4 PortIndex = REG_DWORD8

Manual Number: 00650-146-1 Page 7
Input/Output Connections
The PCI-COM485/8 Serial Communications card uses a 50-pin SCSI D-connector to interface to a
spider cable. The spider cable has eight individual 9-pin connectors provided with it.
To ensure that there is minimum susceptibility to EMI and minimum radiation, it is important that
the card mounting bracket be properly screwed into place and that there be a positive chassis
ground. Also, proper EMI cabling techniques (cable connect to chassis ground at the aperture,
shielded twisted-pair wiring, etc) be used for the input/output wiring.
rebmuNNIPslangiS584-SRrebmuNniPslangiS584-SR
1niPdnuorGDNG62niPdnuorGDNG
2niP+tuoA72niP+tuoE
3niP-tuoA82niP-tuoE
4niPmhO001urhtDNG92niPmhO001urhtDNG
5niP+niA03niP+niE
6niP-niA13niP-niE
7niPdnuorGDNG23niPdnuorGDNG
8niP+tuoB33niP+tuoF
9niP-tuoB43niP-tuoF
01niPmhO001urhtDNG53niPmhO001urhtDNG
11niP+niB63niP+niF
21niP-tuoB73niP-tuoF
31niPdnuorGDNG83niPdnuorGDNG
41niP+tuoC93niP+tuoG
51niP-tuoC04niP-tuoG
61niPmhO001urhtDNG14niPmhO001urhtDNG
71niP+niC24niP+niG
81niP-niC34niP-niG
91niPdnuorGDNG44niPdnuorGDNG
02niP+tuoD54niP+tuoH
12niP-tuoD64niP-tuoH
22niPmhO001urhtDNG74niPmhO001urhtDNG
32niP+niD84niP+niH
42niP-niD94niP-niH
52niPdnuorGDNG05niPdnuorGDNG
Table 1-1: Pin Connections

Manual Number: 00650-146-1Page 8
PCI-COM485/8Manual
Chapter 2: Functional Description
The PCI-COM485/8 Serial Interface Card was designed for effective multipoint transmission in
RS-485 (EIA485) protocol. The card is 7.83 inches long and may be installed in 5-volt PCI-bus
slots of IBM PC or compatible computers. The card features eight independent, asynchronous RS-
485 serial ports, type 16550 buffered UARTS, and, for Windows compatibility, automatic control
to transparently enable/disable the transmission drivers.
RS-485 Balanced Mode Operation
The PCI-COM485/8 supports RS-485 communications and uses differential balanced drivers for
long range and noise immunity. RS-485 operation involves switchable transceivers and the ability
to support multiple devices on a single “party line”. The RS-485 specification defines a maximum
of 32 devices on a single line. The number of devices served on a single line can be expanded by
use of “repeaters”.
PCI-COM485/8 also has the capability to add load resistors to terminate the communications lines.
RS-485 communications requires that one transmitter supply a bias voltage to ensure a known
“zero” state when all transmitters are off.Also, receiver inputs at each end of the network should be
terminated to eliminate “ringing”. The PCI-COM485/8 supports biasing by default and supports
termination by jumpers on the card. If your application requires the transmitter to be un-biased,
please contact the factory.
Comm Port Compatibility
Type 16550 UART’s are used as the Asynchronous Communication Element (ACE). These in-
clude a 16-byte transmit/receive buffer to protect against lost data in multitasking operating sys-
tems, while maintaining 100% compatibility with the original IBM serial port. The system assigns
the address(es).
A crystal oscillator is located on the card. This oscillator permits precise selection of baud rate up
to 115,200 or, by changing a jumper, up to 460,800 with the standard crystal oscillator.
The driver/receiver used, the SN75176B, is capable of driving extremely long communication
lines at high baud rates. It can drive up to ±60 mA on balanced lines and receive inputs as low as
200 mV differential signal superimposed on common mode noise of +12 V or -7 V. In case of
communication conflict, the driver/receivers feature thermal shutdown.
Communication Mode
PCI-COM485/8 supports Half-Duplex communications with a 2-wire cable connection. Half-Du-
plex allows traffic to travel in both directions, but only one way at a time. RS-485 communications
commonly use the half-duplex mode since they share only a single pair of wires.
Baud Rate Ranges
The card has capability for two baud rate ranges and you can select which you wish to use on a
port-by-port basis. One range is up to 115,200 baud applications and the other is up to 460,800
baud.

Manual Number: 00650-146-1 Page 9
Note: Refer to the BAUD RATE DIVISOR VALUE TABLE on page 14 of the manual.
Auto-RTS Transceiver Control
In RS-485 communications, the driver must be enabled and disabled as needed, allowing all cards
to share a two wire cable. The PCI-COM485/8 card controls the driver automatically. With auto-
matic control, the driver is enabled when data is ready to be transmitted. The driver remains en-
abled for one additional character’s transmission time after data transfer is complete and then is
disabled. The receiver is also normally enabled, then disabled during RS-485 transmissions, and
then re-enabled after transmission is completed (plus one character transmission time). The PCI-
COM485/8 automatically adjusts it’s timing to the baud rate of the data. (NOTE: Thanks to the
automatic control feature, the card is ideal for use in WIN95 applications)
Figure 2-1: PCI-COM485/8 Block Diagram
(Only one serial channel shown)

Manual Number: 00650-146-1Page 10
PCI-COM485/8Manual
Chapter 3: Option Selection
To help you locate the jumpers described in this section, refer to the OPTION SELECTION MAP
at the end of this section. Operation of the serial communications section is determined by jumper
installation as described in the following paragraphs.
Terminations
A transmission line should be terminated
at the receiving end in its characteristic
impedance. Installing a jumper at the
locations labeled LDxO applies a 120
load across the transmit/receive
input/output for RS-485 operation.
Simplified Termination Schematic
In RS-485 operations where there are multiple terminals, only the RS-485 ports at each end of the
network should have terminating impedance as described above. To so terminate the COMA port,
place a jumper at the location labeled LDAO. To terminate the COM B, COM C, COM D, COM E,
COM F and COM H ports, place jumpers at locations labeled LDBO, LDCO, LDDO, LDEO,
LDFO and LDHO respectively.
Also, for RS-485 operation, there must be a bias on the RX+ and RX- lines. If the COM485/8 card
is not to provide that bias, contact the factory technical support.
Data Cable Wiring
Signal Connector Pin
Ain- Pin 1
Aout+ Pin 2
Aout- Pin 3
100 Ohm to Ground Pin 5
Ain+ Pin 9

Manual Number: 00650-146-1 Page 11
Baud Rate Ranges
The jumpers labeled CLK X1 and CLK X4 provide means to select baud rates in either of two
ranges. When in the “X1" position, the baud rate range is up to 115,200 baud. When in the CLK X4
position, the baud rate range is 200 to 460,800 baud.
Figure 3-1: PCI-COM485/8 Option Selection Map