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USB Serial Adapter, 4-ports

  • Model: UMC-104
  • In Stock


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Desktop-style commercial strength 4-port USB-RS232 converter optimized for Windows 10, Windows 8 and Windows 7 but will also work fine with Linux, Mac and older operating systems.
With this multi-port USB-RS232 converter you can easily add four RS232 COM ports to almost any computer with a standard USB port. Surge and static protection up to 15KV protects all four COM ports.

This USB-RS232 converter is built around the high-performance and very reliable FT232BL chipset from FTDI Semiconductors which makes it fully compatible with most operating systems, including Linux and Mac (32/64-bit).

This converter is powered by the USB port but can optionally be powered by an external 5VDC supply. An external power supply is usually only required if you connect serial devices which draw a high current or if you connect this converter via a USB hub.

The housing is made of aluminum with hard plastic ends and indication LED lights indicate when data is present on any of the four ports.

Overall features
  • Four individual serial ports
  • Works with most operating systems
  • Easy installation
  • Port-powered from USB bus
  • External power option
  • Supports most serial devices
  • Indication lights for all 4 COM ports
  • USB cable included with each converter

Useful optional accessories
(not included)

Null modem adapter
Null modem adapter

DB9 to RJ45 adapter
DB9 - RJ45 adapter

DB9 gender changer
Gender Changer

Part number UMC-104
Operating system
  • Windows 11, 10, 8.1, 8 (32/64-bit), Windows Server 2016, Windows Server 2012 / R2, Windows 7 (32/64-bit), Windows Server 2008 R2, Vista (32/64-bit), Windows Server 2008 (32/64-bit), XP, Windows Server 2003 (32/64-bit), 2000, (all WHQL compliant). Windows RT as D2XX drivers only.
  • Windows CE v4.2 - 5.2, 6.0, 7.0 and 2013 including: Windows Mobile 2003, 2003 SE, Windows Mobile 5, 6, 6.1 and 6.5
  • Linux (built into kernel 3.0.0-19 and above)
  • Mac OS 8, OS 9, OS X 10.3 to 10.9 and above
  • Android
Processor FTDI FT232BL
Serial driver Analog Devices ADM213
RS232 Interface RS232 DB9 Male x 4
RS232 output power 8.0VDC per port
Cable length 3 feet
USB interface Standard Type B Female
Indication LEDs TX, RX and Power
Ports 4-port
Signals TX, RX, RTS, CTS, DTR, DSR, RI and GND
Power on pin 9 No
Baud rate 300-921,600bps (up to 3Mbps by using alising)
Parity None, Odd, Even, Mark, Space
Data Bits 7, 8
Stop Bits 1, 2
TX / RX buffer size 128 Byte Transmit Buffer / 384 Byte Receive Buffer
Adjustable USB transfer sizes for TX and RX From 64 bytes to 4096 bytes
Adjustable latency timer 1 to 255 msec
Adjustable read and write timeouts 0 to 10000 msec
Flow Control None, Xon/Xoff, Hardware
COM port accessible by Included virtual COM port drivers or FTD2XX.DLL
Special features
Electrostatic (ESD) protection 600W surge protection, 15KV static electricity protection
Power Port powered from USB port. Optional external power (5VDC 1000mA, 3.5 x 1.3 x 7mm barrel connector, center +)
Current draw Static: less than 80mA. Dynamic average: less than 150mA
Housing Aluminum
Dimensions 5.90"(L) x 2.61"(W) x 1.02"(H)
Interface compliance USB1.1,2.0,3.0, EIA/TIA RS-232
Regulatory compliance FCC, CE and RoHS
Operating temp -13°F to 158°F (-25°C to 70°C)
Warranty 1 year limited warranty

For alternative USB to serial solutions please see our full selection of USB to Serial RS232 adapters

Read the Review
Date Added: 11/09/2014 by Eric Sanders
4 of 5 Stars!4 of 5 Stars!
Great converter at a reasonable. 4 serial ports at that price is nice. the converter itself works gr...

Read the Review
Date Added: 09/02/2013 by Stephen Morris
4 of 5 Stars!4 of 5 Stars!
works fine. price and service is resonable. would buy again. Thanks.

Read the Review
Date Added: 07/13/2011 by Becky Staller
5 of 5 Stars!5 of 5 Stars!
First of all I would like to thank usconverters.com for their awesome service and support. Compared ...

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Quick Tip!

Multi-port USB-RS232 Converters

A multi-port USB-RS232 converter is an ideal way of creating multiple RS232 COM ports in any computer using Windows, Mac or Linux. The created COM ports can be found in Windows Device Manager and can be used as if they were built-in serial COM ports. Each COM port can be used individually or simultaneously.

When creating multiple RS232 COM ports it is very important that you are using a good quality USB-RS232 converter with compatible drivers for the operating system you plan to use it on. If you are using a low-cost converter you risk problems such as computer freeze, DLL errors or simply difficulties in communicating with the device you connect to the COM ports. Therefore we usually recommend a converter with a FTDI chipset, since this processor has shown to be compatible with most devices, provides easy installation of the drivers and has an overall good performance without computer freezes or other problems. Other examples of good USB-RS232 chipsets are from Moschip or SilLabs.

Spending a few extra dollars on a good converter can save you much headache and time. Another important step to successful serial communication is proper driver installation. When installing the USB-RS232 adapter drivers you need to pay attention to the driver installation instructions. If you carefully follow the installation instructions you will often save time and frustrations, and have your converter up and running in a few minutes.

For alternative solutions or single port converters please see our selection of USB serial adapters.


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