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