Part#: 2403


USB to 4-Port RS-232, RS-422, RS-485 DB9 Serial Interface Adapter



The SeaLINK® 2403 USB serial I/O adapter provides four RS-232, RS-422, or RS-485 serial ports for USB connectivity to legacy or non-USB compliant devices. Each port is individually configurable for RS-232, RS-422, or RS-485.

Sealevel’s SeaCOM USB software drivers and utilities make installation and operation easy using Microsoft Windows and Linux operating systems. After installing the software, simply connect the 2403 serial interface adapter to your USB port. The device is immediately recognized by the system. Now your non-USB peripherals can have the same connection simplicity and ease of use as USB aware peripherals.

Do you know that adapter design can impact your application? Find out how in this USB Serial performance report.

Additional information

Weight 1.9000 lbs
Dimensions 7.1 x 5.3 x 1.5 in

Communications Chip


Electrical Interface

, ,

High Retention USB

Humidity Range

Host Interface(s)

Max Data Distance

Max Data Rate

Operating Temperature

# of Ports

Power Requirement

RoHS Compliant

Serial Connector(s)

Storage Temperature

USB Powered

USB Specification

  • • Compliant with RoHS and WEEE directives
  • • Each port individually configurable for RS-232, RS-422, or RS-485
  • • High speed UART with 128-byte Tx FIFO and 384-byte Rx FIFO
  • • Data rates to 921.6K bps
  • • Automatic RS-485 enable/disable
  • • Serial and USB activity LEDs
  • • Hot-swappable
  • • Powered by USB connection
  • • Sealevel SeaCOM software supports Windows and Linux operating systems
  • • DB-9M connectors
  • • Includes 6′ USB device cable (Item# CA179)

Windows Software

Software: SeaCOM - Windows

Linux Software

Software: SeaCOM - Linux


Manual: 2403

1 review for SeaLINK+4

  1. Rated 5 out of 5

    Capt. Mike Manager

    Great Product For Our Customers Needs
    I found this product years ago and started using it for transmitting and receiving NMEA 0183 Data between Navigation equipment and a Navigation PC for our Installs on our customers yachts.

    I could not be more happy. Its rock solid, boots to the same comm ports, great drivers and software, I would recommend this product to anyone.

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