SeaLevel SeaLINK+8/USB User manual

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© Sealevel Systems, Inc. 280X Manual | SL9103 1/2023
SeaLINK+8/USB
User Manual | 280X

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© Sealevel Systems, Inc. 280X Manual | SL9103 1/2023
Contents
CONTENTS...........................................................................................................................................................2
INTRODUCTION ................................................................................................................................................... 3
BEFORE YOU GET STARTED ............................................................................................................................... 4
INSTALLATION & CONFIGURATION...................................................................................................................5
PHYSICAL INSTALLATION..................................................................................................................................6
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 ........................................................................................................................................................17

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© Sealevel Systems, Inc. 280X Manual | SL9103 1/2023
Introduction
Overview
The Sealevel Systems SeaLINK+8 family of products equips the PC with 8 USB to Asynchronous serial
ports. Three different model numbers are available that offer a variety of port options. Model 2801 equips
the PC with 8 additional RS-232 ports that support a full RS-232 interface and data rates up to 460.8K baud.
Model 2802 equips the PC with 8 RS-422/485 ports that support data rates up to 921.6K baud and provide
selectable line termination and biasing. 2-wire RS-485 line turnaround is supported via an onboard hardware
circuit. Model 2803 equips the PC with 8 user configurable RS-232/422/485 ports. Each port is individually
configurable, and the interface is selected by configuring two dipswitch positions. 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 IRQs. It does require a system that supports USB both in terms of
hardware and operating system.

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© Sealevel Systems, Inc. 280X Manual | SL9103 1/2023
Before You Get Started
What’s Included
The SeaLINK+8 is shipped with the following items. If any of these items is missing or damaged, contact
the supplier.
•SeaLINK+8 USB to Asynchronous Serial Converter
•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.

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© Sealevel Systems, Inc. 280X Manual | SL9103 1/2023
Installation & Configuration
Software Installation
Windows Installation
Do not install the Adapter in the machine until the software has been fully installed.
Only users running Windows 7 or newer should utilize these instructions for accessing and
installing the appropriate driver via Sealevel’s website. If you are utilizing an operating system
prior to Windows 7, please contact Sealevel by calling 864.843.4343 or emailing
[email protected] to receive access to the proper driver download and installation
instructions.
1. Begin by locating, selecting, and installing the correct software from the Sealevel software
driver database.
2. Type in or select the part number (#2801, 2802, 2803, or 2804) for the adapter from the
listing.
3. Select “Download Now” for SeaCOM for Windows.
4. The setup files will automatically detect the operating environment and install the proper
components. Follow the information presented on the screens that follow.
5. A screen may appear with text similar to: “The publisher cannot be determined due to the
problems below: Authenticode signature not found.” Please click 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.
6. During setup, the user 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 also included
to remove all registry/INI file entries from the system.
7. The software is now installed, and you can proceed with the hardware installation.
To confirm that the SeaCOM driver has been successfully installed, click on the ‘Start’ button, and then
select ‘All Programs’. You should see the ‘SeaCOM’ program folder listed.
You are now ready to proceed with the physical installation of your SeaLINK USB serial adapter.
Windows NT is not USB aware and thus cannot support this device.

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© Sealevel Systems, Inc. 280X Manual | SL9103 1/2023
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 SeaLINK+8 can be connected to any upstream type “A” port, either at the PC host or an upstream hub.
The SeaLINK+8 is hot pluggable, meaning there is no need to power down your computer prior to
installation.
Connect the SeaLINK+8 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 eight 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’s 12 thru 19. However, this assignment will vary from system to system. At this point, the hardware
is recognized and ready to use.

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© Sealevel Systems, Inc. 280X Manual | SL9103 1/2023
Configuration
Factory Configuration
Each device ships from Sealevel Systems with the following configuration.
Model 2801 – SeaLINK+8/232 USB to RS-232 Converter
Contains no user configurable components.
Model 2802 – SeaLINK+8/485 USB to RS-422/485 Converter
RS-422 4-wire full duplex mode selected.
Transmitter always enabled.
Receiver always enabled and terminated and biased as follows:
120ohm terminator between RX+ and RX-
1Kohm pull-up on RX+
1Kohm pull-down on RX-
Model 2803 – SeaLINK+8 USB to RS-232/422/485 Converter
RS-422 4-wire full duplex mode selected.
Transmitter always enabled.
Receiver always enabled and terminated and biased as follows:
120ohm terminator between RX+ and RX-
1Kohm pull-up on RX+
1Kohm pull-down on RX-
In order to change the configuration the box must be opened. Do this by removing the four screws that
attach the two halves of the box.
Electrical Interface Selection
Each port of the SeaLINK+8 models 2802 and 2803 can be individually configured for the specific electrical
interface. Model 2802 supports RS-422/485 while Model 2803 supports RS-232/422/485. This is selectable
via the dipswitch associated with each port. Each of the switch positions is described on the following
page.

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© Sealevel Systems, Inc. 280X Manual | SL9103 1/2023
Below is a figure of dipswitches SW1, SW2, SW3, and SW4. Each switch has a total of twelve positions and
serves to configure two ports. Six positions are used for each port. The default mode of RS-422 4-wire full
duplex is shown.
Figure 1- Dip Switches SW1 - SW4 RS-422 Default Mode
Mode Select Configuration
The first two positions for each port are used to select the electrical interface mode. In RS-422 mode the
transmitter and receiver are always enabled.“485 WE” refers to RS-485 mode with receiver echo. In this
mode the receiver is always enabled. If the card is in 2-wire mode, all transmitted data will be “echoed”
back. “485 NE” refers to RS-485 mode with no receiver echo. In this mode the receiver is enabled only when
no data is being transmitted. In either RS-485 mode the transmitter is only enabled during data
transmission. Refer to the chart below for specific switch settings. Note that this chart appears in the silk
screen on the board as well.
Figure 2- Electrical Interface Mode Selection
ON
12
OFF
3
4
5
6
78
9
10
11
12
PORT 1PORT 2
SW1
M0M1TPU
PU
PD
MODE
M0M1TPUPUPD
MODE
ON
12
OFF
3
4
5
6
78
9
10
11
12
PORT 3PORT 4
SW2
M0M1TPU
PU
PD
MODE
M0M1TPUPUPD
MODE
ON
12
OFF
3
4
5
6
78
9
10
11
12
PORT 5PORT 6
SW3
M0M1TPU
PU
PD
MODE
M0M1TPUPUPD
MODE
ON
12
OFF
3
4
5
6
78
9
10
11
12
PORT 7PORT 8
SW4
M0M1TPU
PU
PD
MODE
M0M1TPUPUPD
MODE
SWITCH
232
MODE SELECT
422
485 WE
485 NE
OFF OFF
M1 M0
OFF
OFF
ON
ON
ON ON

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© Sealevel Systems, Inc. 280X Manual | SL9103 1/2023
Interface Biasing Configuration
The last four positions for each port are used to select the line termination and bias settings. Refer to the
chart below for specific switch settings of the three supported electrical interface modes. Note that this
chart appears in the silk screen on the board as well.
PD = 1Kohm pull-down resistor connected to RX-
RS-232 mode = always OFF
RS-422 mode = always ON
RS-485 mode = ON if not provided by another device on the bus
PU = 5.1Kohm pull-up resistor connected to CTS+
RS-232 mode = always OFF
RS-422 mode = always ON
RS-485 mode = always ON
PU = 1Kohm pull-down resistor connected to RX+
RS-232 mode = always OFF
RS-422 mode = always ON
RS-485 mode = ON if not provided by another device on the bus
T = 120ohm terminating resistor connected between RX+ and RX-
RS-232 mode = always OFF
RS-422 mode = always ON
RS-485 mode = ON if physically located at one end of bus
Figure 3 - Electrical Interface Termination and Biasing Selection
Contrary to some of our other products, there are no provisions on board for looping TX+ to RX+ and
TX- to RX- for 2-wire RS-485 mode. These connections must be made externally inside the mating
DB-9 connector. Refer to the RS-422 pinout diagram for the appropriate pin numbers.
SWITCH
232
INTERFACE BIASING
422
485
OFF OFF
PD PU
ON
ON
ON
ON
OFF OFF
PU T
ON
ON*
ON
ON
* = IF END OF 485 BUS

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© Sealevel Systems, Inc. 280X Manual | SL9103 1/2023
Technical Description
The SeaLINK+8 utilizes eight 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-232/422/485 transceiver supports data
rates up to 921.6K baud for RS-422/485 and 460.8K baud for RS-232.
Features
•Hot pluggable device that does not require opening the case
•No system resources are required (i.e. I/O ports or IRQs)
•LED status indicators for power 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
RS-232 (DB-9 Male)
Signal
Name
Pin #
Mode
GND
Ground
5
TX
Transmit Data
3
Output
RTS
Request To Send
7
Output
DTR
Data Terminal Ready
4
Output
RX
Receive Data
2
Input