Home SEALEVEL | USB Serial Adapters SeaI/O-681U: USB to 8-Port RS-232 Serial Adapter
Image 1
SEALEVEL | USB Serial Adapters

SeaI/O-681U: USB to 8-Port RS-232 Serial Adapter

Now includes NABL Calibration Certificate.
Rs. 62992.00

The SeaI/O-681U is an 8-port USB-to-RS-232 serial adapter designed for rugged industrial and embedded systems. Housed in a durable enclosure with RJ45 connectors and high-speed USB UART, it delivers seamless multi-port serial expansion over USB..

Quantity:
- +
Product added to cart successfully
  • Detail
  • Special Features
  • Specification

The SeaI/O-681U makes it easy to integrate eight RS-232 serial ports into any industrial or embedded application with a USB interface. Supporting up to 921.6K bps per port, it handles high-throughput communication while maintaining low host CPU usage through a robust state-machine USB/UART design.
Each port uses RJ45 connectors with integrated Tx/Rx LEDs, and the adapter itself fits neatly into industrial setups, including SeaPAC touchscreens or Relio systems.
The 681U also provides a high-retention USB port and rugged construction for long-term deployment in automation, control, or data collection environments.
An RS-485 pass-through expansion header allows integration with Sealevel’s N-series modules, offering a scalable path to additional I/O channels.

  1. Adds 8 RS-232 ports via one USB connection

  2. Enclosed design with industrial-grade RJ45 connectors

  3. Supports data rates up to 921.6K bps

  4. State-machine architecture reduces CPU overhead

  5. High-retention USB Type B port prevents cable disconnection

  6. Status LEDs on each port for Tx/Rx visibility

  7. Powered via 9–30VDC external supply with fused output on RJ45 pin 5

  8. RS-485 pass-through connector supports up to 246 expansion modules

  9. Appears as standard COM ports in Windows and Linux

  10. Ideal for industrial PCs, SeaPAC HMIs, or SeaI/O stacks

Parameter Value
Model SeaI/O-681U
Host Interface USB
Number of Ports 8
Serial Interface RS-232
Serial Connector(s) RJ45
Max Data Rate 921.6K bps
Max Data Distance 50 feet
Power Requirement 9–30VDC @ 1.5W
USB Powered No (requires external power input)
USB Specification USB 1.1 Compliant; USB 2.0 Compatible
Dimensions 7.5" (L) x 5.1" (W) x 1.3" (H)
Operating Temperature 0°C to 70°C (32°F to 158°F)
Storage Temperature -50°C to 105°C (-58°F to 221°F)
Humidity Range 10–90% Relative Humidity, Non-Condensing
Communication Chip USB/UART
High Retention USB Yes
Expansion Support RS-485 pass-through for N-series modules
Product Family SeaI/O
Board or Enclosure Enclosure