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RR-CirKits LocoBuffer-USB for connecting PC without a serial interface to LocoNet.

For Loconet users, the LocoBuffer-USB is a convenient device that will let you connect your computer through a USB port to your layout. Here is a picture of the LocoBuffer-USB made by RR-CirKits:

The real RR-CirKits LocoBuffer-USB.

See the RR-CirKits Home Page for more information.

Older Versions

RR-CirKits made an older version of the LocoBuffer for RS-232 Serial Ports that has not been tested with Rocrail. The LocoBuffer-USB 2.0 version has been tested and works with Rocrail.


Under Windows, you must install the correct driver for the LocoBuffer. Once that is done, you will need to know the COM port that it is using. You can find this out by using Start > Control Panel > System > Device Manager:

In this example, the LocoBuffer is running as COM4. You should set your Controller to use COM4 to talk to your Loconet devices.

Here is a screenshot of a DCS100 using LocoBuffer on COM4:


This is what the DIGINT section of your rocrail.ini file should look like after setting your controller to use COM4:

  <digint iid="DCS100" lib="loconet" device="com4" host="" port="0" swtime="0" bps="57600" sublib="serial" libpath=".">
    <loconet purgetime="200" useidle="false">
      <options store="false" opsw="0000100011000000000000000000000000000000000000000000000000000000"/>

Note that while the LocoBuffer will work once Rocrail is configured to the correct COM port and a baudrate of 57.6K.


You need the latest version of the FTDI drivers to run LocoBuffer. These drivers have been included in the Linux kernel as of [version TK,]. However, for Ubuntu 7.10, the driver is out of date, and you will need to copy a newer version into your /lib/modules/… directory. See the RR-CirKits home page (link above) for more information.

Once the correct driver is installed, it should be listed in your /dev directory as "ttyUSBx", where x is the number of the USB connection it is running on.

The LocoBuffer-USB is accessible through /dev/ttyUSB1 in this example.

And for the LocoBuffer-USB you need a baudrate of 57.6K:

  <digint iid="loconet_1" lib="loconet" device="/dev/ttyUSB1" bps="57600" sublib="serial">
    <loconet cmdstn="db150" purgetime="200" useidle="true">
      <options opsw="0010010000100000011000000110000001100000001000000010000000000000" store="false"/>

These lines are written in the system log after pluggin in the LocoBuffer-USB:

kernel: [17180906.584000] usb 1-1.3.1: configuration #1 chosen from 1 choice
kernel: [17180906.828000] drivers/usb/serial/usb-serial.c: USB Serial support registered for FTDI USB Serial Device
kernel: [17180906.828000] ftdi_sio 1-1.3.1:1.0: FTDI USB Serial Device converter detected
kernel: [17180906.828000] drivers/usb/serial/ftdi_sio.c: Detected FT232BM
kernel: [17180906.828000] usb 1-1.3.1: FTDI USB Serial Device converter now attached to ttyUSB1
kernel: [17180906.828000] usbcore: registered new driver ftdi_sio
kernel: [17180906.828000] drivers/usb/serial/ftdi_sio.c: v1.4.3:USB FTDI Serial Converters Driver

Diagram and firmware

locobuffer-usb-en.txt · Last modified: 2018/11/12 08:56 by