USB to RS-232 DB9 Serial Interface Adapter — 60 inches

Part: 2105R   Model: SeaLINK+232-DB9

(13 customer reviews)


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The SeaLINK® single-port USB to RS-232 DB9 serial adapter utilizes Sealevel’s expertise in military-grade designs by incorporating a ruggedized, over-molded enclosure into the 2105R. This improves the reliability and durability in industrial and mobile applications such as GPS navigation systems, barcode readers, signature input devices, serial printers, scales, and similar applications.

The 2105R features programmable baud rate and data formats with 128-byte transmit and 384-byte receive buffers. The USB serial adapter is compatible with all standard PC baud rates and supports high-speed communication to 921.6K bps. The 2105R is powered by the USB port and status LEDs molded into the enclosure indicate serial data activity and connection to the host.

Sealevel SeaCOM USB software drivers and utilities make installation and operation easy using Microsoft Windows and Linux operating systems. After installing the software, simply plug the 2105R into an available USB port and the serial port is recognized as a standard COM port by the host system enabling compatibility with legacy software.

The attached cable is approximately 56 inches long and fully shielded to protect the 2105R from RF and EMI interference that is common in mobile and industrial environments. Standard operating temperature range is 0°C to 70°C (32°F to 158°F), and an extended temperature range of -40°C to 85°C (-40°F to 185°F) is optional.

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

The 2105R has a DB-9M connector. If you need a DB-25M connector, order the 2101.


Additional information



Communications Chip



Overmold: 2.24" (L) x 1.3" (W) x 0.6" (H)Overall Length: 60"

Electrical Interface


Humidity Range

10 – 90% Relative Humidity, Non-Condensing

Host Interface(s)


Max Data Distance

50 feet

Max Data Rate

921.6K bps

Operating Temperature

0°C to 70°C (32°F to 158°F)

# of Ports


Power Requirement

+5V @ 100mA

RoHS Compliant


Serial Connector(s)


Storage Temperature

-50°C to 105°C (-58°F to 221°F)

USB Powered


USB Specification

1.1 Compliant, 2.0 Compatible

  • Compliant with RoHS and WEEE directives
  • Rugged, military-grade enclosure improves durability in mobile and industrial applications
  • High-speed UART with 128-byte Tx FIFO and 384-byte Rx FIFO
  • Programmable baud rate and data formats
  • Supports data rates to 921.6K bps
  • Status LEDs molded into enclosure indicate serial data activity and connection to host
  • All modem control signals implemented
  • Powered by USB host connection
  • Sealevel SeaCOM software supports Windows and Linux operating systems
  • Attached cable is approximately 56 inches in length
  • Overall length is 60 inches
  • Standard DB-9M serial connector
  • Made in the USA
  • Lifetime Warranty

Windows Software

Software: SeaCOM - Windows

Linux Software

Software: SeaCOM - Linux


Datasheet: 2105R

13 reviews for SeaLINK+232-DB9

  1. philemi

    best adapter on the market
    We have been using the 2105 and now the 2105r for years. Great adapter, works well, have never had one fail

  2. rick

    Will and Bryant…….the greatest!!
    I have always needed tech support for anything I’m doing with computers 🙂 , but this experience far and away tops them all. Microsoft and the rest of the companies with their phony tech support people (they call it customer service—ha ha!) can’t even begin to compare with the effort you guys make. Thank you thank you!! Will and Bryant are off the charts!

  3. Forest

    Great customer service
    Your Tech Support of my problem which was critical to my navigation while heading south aboard my sail boat was fantastic. You handled a difficult problem in a very professional way. My hat is off to Bryant and Will

  4. Desi

    Best Serial Adapter on the Market
    Been using this adapter for the past 5 years with XP.
    Now upgraded to Windows 7 and has worked flawlessly with the new Opeating system

  5. Drcalvert

    Using the 2105R on Natural Gas Transmission Pipeline
    I run the RTU lab for a major transmission pipeline co. out of Houston, TX. I determine whether, hardware and/or software will perform as vendors specify. I have found and recommend the 2105R for all USB to serial communications. One of the biggest sell points for me is the Tx/Rx LEDS. This is great when in troubleshooting mode

  6. Kerry

    Customer service/Technical Support
    Outstanding technical and customer support over the last couple of years. They have never let me down, even when I was the one that made the mistake.

  7. Justin

    Works for everyhting I’ve tried
    These adapters have worked with every specialized piece of equipment I’ve tried.

  8. OME

    2105R works great!
    2105R USB converter works great when interfacing a computer to a GPS. The unit has no annoying “drops” that we’ve experienced with other converters.

  9. Brian M

    Serial Adapter
    After spending many months and paying technicians hundreds of dollars to fix our “communication” problem between our transmitters and our base computer, we tried the 2105R adapter from Sealevel and it has worked perfectly. Wish we would have started with Sealevel first. I rate 5 stars for this adapter and to the company itself.

  10. Gray

    It has never failed to communicate with any Variable Frequency Drive, Radio, or Programmable Logic Controller I have used it with.
    The Sealevel 2105R has been by far the most reliable product of its kind that I have owned. I have
    tried other reputable “equivlent” products but every one has failed while attaching to one device or
    another. The Sealevel product has never failed no matter what serial device I have
    used it on.

  11. Jeff Stewart

    High quality and robust
    I have had an off brand adapter for a couple of years. I bought the 2105R for firmware downloads through IrDa. It used to take 45 minutes to complete this and with my 2105R it now takes 15. It is a good product that is robust.

  12. Bob

    USB-Serial Communication
    I’ve used many different USB-Serial adapters to utilize older hardware with modern computers with no serial ports. Some work better than others, but this SeaLevel cable blows away all competition with drivers that actually work as intended, LED feedback that reflects realistic functionality, and the correct transposing of the rarely-supported serial lines like DCD. Thanks!

  13. JJ

    Used to connect an older weather station to a Acer Aspire One Cloudbook running Linux. The 2105R worked as designed. Great device!

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