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For shipping to USA only. Please send inquiries to for the rest of Americas.
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For shipping to USA only. Please send inquiries to for the rest of Americas.
Please visit for other regions.

USB to RS232 adapters w/Optical Isolation (Full Speed)

SKU ES-U-1101-MB

The ES-U-1101-MB USB-to-Optical isolated RS-232 Serial Adapter is designed to make serial port expansion quick and simple. Connecting to a USB port on your computer or USB hub, the USB Serial Adapter instantly adds a high speed RS-232 serial communication port to your system. By taking advantage of the USB bus, the USB Serial Adapter makes it easier than ever to add serial ports and serial devices to your system with easy plug-and-play and hot plug features.

By plugging the USB Serial Adapter to the USB port, the adapter is automatically detected and installed. There are no IRQ & COM port conflicts, since the port doesn't require any additional IRQ, DMA, memory as resources on the system. The adapter is powered by the USB port, and no external power adapter is required. The adapter is complete with a DIN rail bracket for industrial environment. Three monitoring LEDs are on the upper case indicating the power status and TX/RX port status for easy diagnostics.

Optical isolation and surge protection are integral to the ES-U-1101-MB. The serial line of the RS-232 port is optically isolated with 2000 volt DC optical isolation. The optical isolation protects your PC from spikes and surges on the RS-422/485 network, by converting the electrical pulse into an optical signal and then changing it back into an electrical pulse. The surges and spikes cannot cross the optical link. The adapter has a built-in surge protector to withstand electrostatic discharge and power surges up to 25KV ESD.

The ES-U-1101-MB USB to Optical isolated Serial Adapter provides instant connectivity with modems, ISDN TAs, PDAs, handheld & pocket PCs, digital cameras, POS, serial printers. It is suitable for remote access, retail and industrial applications, data collection and other applications requiring high speed RS-232 serial communication port. The ES-U-1101-MB USB to Industrial RS-232 port provides industrial solution of a reliable & fast RS-232 port for harsh environment. 

Complete driver support for Windows 10, 8.1, 8, 7, Vista, XP, 2000, ME, 98, Server 2012 & 2008, Linux, MAC-OS8, 9, X


  •  Adds one optical isolated serial port by connecting to USB port 
  •  Installed as standard Windows COM port
  • 2000V DC optical isolation protection
  • 25KV ESD surge protection
  • Full RS-232 modem control signals 
  • RS-232 data signals: TxD, RxD, RTS,CTS, DSR, DTR, DCD, RI, GND
  • FIFO: 128 byte transmit buffer 384 byte receive buffer 
  • Serial port speed up to 460K bps
  • One DB9 male connector
  • Full hardware and software flow control
  • 2KV DC optical isolation protection
  • ESD surge protection (25KV)
  • Monitor LEDs of Power, TxD, RxD indicating power & port status
  • Serial Communication Parameters:

     -Parity: None, Even, Odd 
     -Data bits: 7, 8 
     -Flow control: RTS/CTS , DSR/DTR, X-ON/  X-OFF, None 

  • USB cable of 0.9 meter included 
  • Powered by USB port. No external power adapter required. 
  • Easy plug & play installation and RS-232/RS-422/RS-485 device connection 
  • Industry Standard FTDI chip set & drivers for maximum compatibility
  • Works with USB 1.1 & 2.0 host port
  • SECC sheet metal chassis; DIN rail bracket available seperately
  • Dimensions: 57mm x 76mm x 23mm    82mm x 76mm x 23mm (with DIN rail bracket) 
  • COM Port Number assignment is configurable
  • Supports Windows 10, 8.1, 8, 7, Vista, XP, 2000, ME, 98, Server 2012 & 2008, Linux, MAC-OS8, 9, X
Document Type Version File
Manual 1.3 Download
Product Change Notification (PCN) Download

Download Virtual COM Port (VCP) Drivers for Windows, Mac OS and Linux

Order information
Part Number  Ports Housing



Updated version from ES-U-1101-M [USB-COM-Si-M] to support higher data throughput)

Din Rail Bracket (DR-201) the rank mount clip is available for sales. If required, please contact us at

1 Metal USB-B  w/Isolation

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