Edit on GitHub


USB Downloader is an interface to connect the USB port of PC and the 4-pin port of the controller through serial communication.


USB Downloader(LN-101)

(May cause serious injury or death)

  • Never place items containing water, flammables, and solvents near product.
  • Never place fingers, arms, toes, and other body parts near product during operation.
  • Cut power off if product emits strange odors or smoke.
  • Keep product out of reach of children.
  • Check the power’s polarity before wiring.

(May cause injury or damage to product)

  • Comply with the operating environment such as voltage and temperature.
  • Do not insert sharp blades nor pins during product operation.

(May cause injury or damage to product)

  • Do not disassemble or modify product.
  • Do not drop or apply strong shock to product.

How to Use

Connect the LN-101 to a serial port on your controller. The following images show the example of interfacing ROBOTIS controller with PC.


LN-101 with CM-100


LN-101 with CM-700 connected.

Serial Communication

Available Controller

NOTE : Difference in voltage may cause unstable LN-101 connections. Ensure that both connecting equipment and PC are properly grounded.

Check Driver

How to check whether the USB downloader(LN-101) driver is installed correctly.

  1. Connect USB Downloader (LN-101) to the USB Port of PC.


  2. Select Manage in the popped-up menu shown by right-clicking My Computer.


  3. Check USB Serial Converter in Universal Serial Bus Controllers of Device Manager.


  4. Check USB Serial Port(COMx) in the list of Ports(COM & LPT). COM Port number may vary depending on each system.


Install Driver Manually

If you installed RoboPlus, FTDI Driver (USB2DYNAMIXEL, USB Downloader (LN-101) driver) is installed together automatically. If you didn’t install the RoboPlus yet, or if the driver is not installed appropriately, please install it manually according to following procedures.

  1. Connect a device to PC. If the driver is not installed yet, Found New Hardware Wizard will be popped up. Install from a list or specific location (Advanced)(S) -> Next(N)


  2. Decide the location of Driver. If RoboPlus S/W has been installed automatically, the driver is in LN101 folder of RoboPlus Installation folder. Or if you want to install the newest version, download the newest version VCP driver from FTDI Driver Download page.



  3. Click the Next(N) button to start the installation. Installation of USB Serial Converter driver is completed.


  4. Install the USB Serial Port driver in the same way.


Connector Information

Item TTL
PCB Header


Setting up the port