SeaLevel SeaPORT+2/485 User manual

© Systems, Inc. 2202 Manual | SL9097 6/ Sealevel 2021
SeaPORT+2/485
User Manual | 2202

© Systems, Inc. 2202 Manual | SL9097 6/ Sealevel 2021
Contents
CONTENTS...........................................................................................................................................................2
BEFORE YOU GET STARTED ...............................................................................................................................4
INSTALLATION INSTRUCTIONS .........................................................................................................................5
CONFIGURATION .................................................................................................................................................7
TECHNICAL DESCRIPTION ...............................................................................................................................10
SPECIFICATIONS ...............................................................................................................................................11
APPENDIX A –TROUBLESHOOTING................................................................................................................12
APPENDIX B –HOW TO GET ASSISTANCE .....................................................................................................13
APPENDIX C –ELECTRICAL INTERFACE ........................................................................................................14
APPENDIX D –ASYNCHRONOUS COMMUNICATIONS ..................................................................................15
APPENDIX E –COMPLIANCE NOTICES...........................................................................................................16
WARRANTY ........................................................................................................................................................18

© Systems, Inc. 2202 Manual | SL9097 6/ Sealevel 2021
Introduction
The Sealevel Systems equips the PC with 2 USB to RS-422/485 Asynchronous serial ports providing a
versatile interface for common serial needs. The advantage of this product over more traditional
approaches is that it does not require opening the computer case, nor does it require resources such as I/O
ports or IRQ’s. It does require a system that supports USB both in terms of hardware and operating system.

© Systems, Inc. 2202 Manual | SL9097 6/ Sealevel 2021
Before You Get Started
What’s Included
The SeaPORT+2/485 is shipped with the following items. If any of these items is missing or damaged,
contact the supplier.
•SeaPORT+2/485 USB to RS-422/485 Serial I/O Adapter
•USB Cable Part Number CA179 for Connecting to Upstream Host/Hub
Advisory Conventions
Warning
The highest level of importance used to stress a condition where damage could result to the
product, or the user could suffer serious injury.
Important
The middle level of importance used to highlight information that might not seem obvious or a
situation that could cause the product to fail.
Note
The lowest level of importance used to provide background information, additional tips, or other
non-critical facts that will not affect the use of the product.

© Systems, Inc. 2202 Manual | SL9097 6/ Sealevel 2021
Installation Instructions
Windows 98/ME/2000/XP/Vista™ Operating Systems
Do not connect the device to a USB port until the software is installed.
1. Begin by locating, selecting, and installing the correct software from the Sealevel software driver
database.
2. Select the Part Number (2202) for your device from the listing.
3. The setup file will automatically detect the operating environment and install the proper
components. Follow the information presented on the installation screens that follow.
4. A screen may appear with the declaration: “The publisher cannot be determined due to the
problems below: Authenticode signature not found.” Please select the ‘Yes’ button and proceed
with the installation. This declaration simply means that the Operating System is not aware of the
driver being loaded. It will not cause any harm to your system.
5. During setup, you may specify installation directories and other preferred configurations. This
program also adds entries to the system registry that are necessary for specifying the operating
parameters for each driver. An uninstall option is included to remove the driver and all registry/INI
file entries from your system.
6. Proceed with the physical installation of your SeaLINK USB serial adapter.
Windows NT is not USB aware and thus cannot support this device.

© Systems, Inc. 2202 Manual | SL9097 6/ Sealevel 2021
Physical Installation
The screen captures below are taken from a Windows 98 installation. Your particular operating system
may differ slightly from what is shown based on your version of Windows.
The SeaPORT+2/485 can be connected to any upstream type “A” port either at the PC host or an upstream
hub. The SeaPORT+2/485 is hot pluggable, meaning there is no need to power down your computer prior
to installation.
Connect the SeaPORT+2/485 to an upstream host or hub.
The New Hardware Found wizard will now proceed to locate the appropriate drivers. These drivers were
installed during the SeaCOM software setup procedure. Once the drivers are found a new window will pop
up indicating the installation of each of the four new ports.
If you view the system’s Device Manager, you should have new “COM” ports in the Ports (COM& LPT) Device
Class. This is shown on the following page.
You can access your new COM: ports by using the assigned COM: identifiers as shown above. In this case,
it is COM 3 and 4. However, this assignment will vary from system to system. At this point, the hardware is
recognized and ready to use.

© Systems, Inc. 2202 Manual | SL9097 6/ Sealevel 2021
Configuration
Original Configuration
This device ships from Sealevel Systems with the following configuration.
422 mode,
120 ohm termination,
1K ohm pull up on RX+
1K ohm pull down on RX-
In order to change this configuration, the box must be opened. Do this by removing the four screws located
on the bottom. When reassembling please note that the top and bottom are keyed to fit in only one direction.
Electrical Interface Selection
Each of the two ports on the SeaPORT+2/485 can be individually configured as an RS-422, or RS-485
interface. This is selectable via the DIP switches and DIP shunts. Each of the switch positions is described
on the following page.

© Systems, Inc. 2202 Manual | SL9097 6/ Sealevel 2021
Switch Descriptions
Figure 1: Switche SW4
L485 option, OFF for 422.
OFF: No effect
ON : Connects TX+ to RX+ for two-wire operation
L485 option, OFF for 422.
OFF: No effect
ON : Connects TX- to RX- for two-wire operation
PU 485 option, OFF for 422.
OFF: No effect
ON : Adds a 1 K ohm pull-up resistor to RX+
PD 485 option, OFF for 422.
OFF: No effect
ON : Adds a 1 K ohm pull-down resistor to RX-
T422 and 485 option.
OFF: No effect
ON : Adds a 120 ohm termination resistor between RX+ and RX-
ON
1 2 3 4 5 6 7 8
OFF 910
Port 1
L
L
T
PU
PD
Port 2
L
L
T
PU
PD
SW4

© Systems, Inc. 2202 Manual | SL9097 6/ Sealevel 2021
Switch Examples
Figure 2: RS422/485 Interface Configuration
485 Mode Selection
OFF : 422 Mode
The transmitter lines TX+ and TX- are always driven
ON : 485 Mode
The transmitter lines TX+ and TX- are switched to high impedance when the device is
not actively transmitting data
NE 485 option, OFF for 422
OFF : The receiver is always enabled. In a two-wire setup the receiver will echo back all
transmitted data.
ON : The receiver is disabled when the transmitter is enabled. In a two-wire setup the receiver
will not echo back transmitted data.
Switch positions 1 and 2 are for port 1 and switch positions 3 and 4 for port 2.
ON
1 2 3 4
OFF
485 1
NE 1
485 2
NE 2
SW3

© Systems, Inc. 2202 Manual | SL9097 6/ Sealevel 2021
Technical Description
The SeaPORT+2/485 utilizes two USB UARTs. These chips feature programmable baud rate, data format,
128 byte Dual Port TX Buffer, and 384 byte Dual Port RX Buffer. The RS-422/485 transceiver supports data
rates up to 921.6K baud.
Features
•Hot pluggable device that does not require opening the case
•No system resources are required (i.e., I/O ports or IRQ’s)
•LED status indicators for USB Enabled and port activity
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

© Systems, Inc. 2202 Manual | SL9097 6/ Sealevel 2021
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
Physical Dimensions
Package Length
7.06 inches (17.93 cm)
Package Width
5.32 inches (13.51 cm)
Package Height
1.50 inches (3.81 cm)
Mean Time Between Failures (MTBF)
Greater than 150,000 hours. (Calculated)
Manufacturing
All Sealevel Systems Printed Circuit boards are built to UL 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
This device is a high-power USB device. It must be plugged into the USB root hub or a self-powered hub
capable of supplying 500 mA per port.

© Systems, Inc. 2202 Manual | SL9097 6/ Sealevel 2021
Appendix A –Troubleshooting
Serial Utility test software is supplied with the Sealevel Systems adapter and will be used in the
troubleshooting procedures. Using this software and following these simple steps, most common
problems can be eliminated without the need to call Technical Support.
1. If your adapter isn’t working, first check to make sure that USB support is enabled in the System
BIOS, and it is functioning properly in the operating system. This can be done by using either the
Windows 98/ME or Windows 2000 Device Manager.
2. Ensure that the Sealevel Systems software has been installed on the machine so that the necessary
files are in place to complete the installation.
3. When the SeaPORT+2/485 is configured properly, the USB Enabled LED (E) will be lit. This should
allow you to use Sealevel’s WinSSD utility and the supplied loopback plug to check
communications. The supplied loopback plug connects TD to RD. If you decide to test the Modem
Control Signals, a full pin loopback plug will be required. Details on loopback plugs are included
on WinSSD. Contact Sealevel Systems if you need further assistance.
4. When testing the SeaPORT+2/485 in loopback mode, you should see the port LED’s flashing as
well as seeing echoed data on the screen. The loopback test first transmits a HEX pattern, 55AA,
and then a ASCII string of data. If this test passes, then the SeaPORT+2/485 is ready for use in your
application.
5. Please note that if the adapter is configured for 2 wire RS-485 with no echo a loopback test is not
possible. The receiver in this case will be turned off and the test will fail. If you plan on using this
device in two wire mode test the adapter in RS-422 mode first. Then configure the adapter for your
application.
If these steps do not solve your problem, please call Sealevel Systems’ Technical Support, [phone].
Our technical support is free and available from 8:00AM-5PM Eastern Time, Monday through Friday. For
email support contact: supp[email protected].

© Systems, Inc. 2202 Manual | SL9097 6/ Sealevel 2021
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 connected in a computer ready to run diagnostics.
3. Sealevel Systems maintains a home page on the Internet. Our home page address is
www.sealevel.com. The latest software updates, and newest manuals are available via our FTP
site that can be accessed from our home page.
4. Technical support is available Monday thru Friday from 8:00 a.m. to 5:00 p.m. Eastern time.
Technical support can be reached at [phone].
RETURN AUTHORIZATION MUST BE OBTAINED FROM SEALEVEL SYSTEMS BEFORE RETURNED
MERCHANDISE WILL BE ACCEPTED. AUTHORIZATION CAN BE OBTAINED BY CALLING SEALEVEL
SYSTEMS AND REQUESTING A RETURN MERCHANDISE AUTHORIZATION (RMA) NUMBER.

© Systems, Inc. 2202 Manual | SL9097 6/ Sealevel 2021
Appendix C –Electrical 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.
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.

© Systems, Inc. 2202 Manual | SL9097 6/ Sealevel 2021
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. Character
boundaries for asynchronous communications are defined by a starting bit followed by a pre-defined
number of data bits (5, 6, 7, or 8). 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.
Figure 3 - Asynchronous 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 referred 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.

© Systems, Inc. 2202 Manual | SL9097 6/ Sealevel 2021
Appendix E –Compliance Notices
Federal Communications Commission (FCC) Statement
This equipment has been tested and found to comply with the limits for Class B 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
residential installation. 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. However, there is no guarantee that
interference will not occur in a particular installation. If this equipment does cause harmful
interference to radio or television reception, which can be determined by turning the
equipment off and on, the user is encouraged to try to correct the interference by one or
more of the following measures:
•Reorient or relocate the receiving antenna
•Increase the separation between the equipment and receiver
•Connect the equipment into an outlet on a circuit different from that to which the
receiver is connected
•Consult the dealer or an experienced radio/TV technician for help
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 B - “Limits and methods of measurement of radio interference
characteristics of information technology equipment”
•EN55024 –“Information technology equipment Immunity characteristics Limits
and methods of measurement”.
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.

© Systems, Inc. 2202 Manual | SL9097 6/ Sealevel 2021
Caution
Sealevel Systems, Inc. is not responsible for any radio or television interference caused by unauthorized
modifications of this equipment or the substitution of attachment of connecting cables and equipment
other than those specified by Sealevel Systems. Such unauthorized modifications, substitutions, or
attachments may void the user’s authority to operate the equipment. The correction of interference caused
by such unauthorized modifications, substitutions, or attachments will be the responsibility of the user.
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 directives.
Canadian Radio Interference Regulations
This Class B digital apparatus meets all requirements of the Canadian Interference-Causing Equipment
Regulations.
Cet Appareil numérique de la classe B respecte toutes les exigences de Règlement sur le matériel du
Canada.

© Systems, Inc. 2202 Manual | SL9097 6/ Sealevel 2021
Warranty
Sealevel's commitment to providing the best I/O solutions is reflected in the Lifetime Warranty that is
standard on all Sealevel manufactured I/O products. We are able to offer this warranty due to our control
of manufacturing quality and the historically high reliability of our products in the field. Sealevel products
are designed and manufactured at its Liberty, South Carolina facility, allowing direct control over product
development, production, burn-in and testing. Sealevel achieved ISO-9001:2015 certification in 2018.
Warranty Policy
Sealevel Systems, Inc. (hereafter "Sealevel") warrants that the Product shall conform to and perform in
accordance with published technical specifications and shall be free of defects in materials and
workmanship for the warranty period. In the event of failure, Sealevel will repair or replace the product at
Sealevel's sole discretion. Failures resulting from misapplication or misuse of the Product, failure to adhere
to any specifications or instructions, or failure resulting from neglect, abuse, accidents, or acts of nature
are not covered under this warranty.
Warranty service may be obtained by delivering the Product to Sealevel and providing proof of purchase.
Customer agrees to ensure the Product or assume the risk of loss or damage in transit, to prepay shipping
charges to Sealevel, and to use the original shipping container or equivalent. Warranty is valid only for
original purchaser and is not transferable.
This warranty applies to Sealevel manufactured Product. Product purchased through Sealevel but
manufactured by a third party will retain the original manufacturer's warranty.
Non-Warranty Repair/Retest
Products returned due to damage or misuse and Products retested with no problem found are subject to
repair/retest charges. A purchase order or credit card number and authorization must be provided in order
to obtain an RMA (Return Merchandise Authorization) number prior to returning Product.
How to obtain an RMA (Return Merchandise Authorization)
If you need to return a product for warranty or non-warranty repair, you must first obtain an RMA number.
Please contact Sealevel Systems, Inc. Technical Support for assistance:
Available Monday –Friday, 8:00AM to 5:00PM EST
Phone [phone]
Email [email protected]
Trademarks
Sealevel Systems, Incorporated acknowledges that all trademarks referenced in this manual are the service
mark, trademark, or registered trademark of the respective company.