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DTC User Guide (Community Supported)

Table of contents

  1. Overview
  2. Requirements
    1. Hardware
    2. Software
      1. VOXL2
      2. VOXL
  3. Hardware Setup
    1. VOXL Hardware Setup
      1. Using M0078
    2. Ground Station Hardware Setup
  4. Software Setup
    1. Configure Radios
    2. VOXL2 Software Setup
    3. Ground Station Software Setup
  5. Connecting to QGroundControl


VOXL and VOXL2 support the ability to quickly and easily add a DTC wireless connection to a Ground Control Station. The following guide provides you the necessary details to do so.

Below are some helpful links from DTC:

DTC Products

BLUSDR-6 Datasheet

BluSDR-6 Modem

As this is a community supported modem the ModalAI team cannot provide direct support. Instead please direct questions to or



The following ModalAI hardware is required to establish a DTC network connection between a VOXL-based product and a host device (computer, tablet, etc.).

Part NumberDescriptionLink
MCCA-M0078VOXL USB Expansion Board v2Purchase
MCCA-M0041Power Module v3Purchase
M0006, M0019, or M0054VOXL, VOXL-Flight, or VOXL2Purchase links: VOXL2, VOXL-Flight, VOXL


In order for the required drivers to be available on target, the following software is required:



Note: Currently, voxl-modem 0.17.0 is not installed with any platforms, so you will need to install it.

Installing voxl-modem 1.0.7 on VOXL2:

adb push voxl-modem_1.0.7_arm64.deb /
adb shell dpkg -i /voxl-modem_1.0.7_arm64.deb

Hardware Setup

Below is a list of required hardware in order to create a connection between a VOXL-based device and a ground control station via. DTC BluSDR modems.

QTYPart NumberDescriptionNotes
1MCCA-M0078-2VOXL USB Expansion Board v2Purchase
1MCCA-M0041-BPower Module v3Purchase
1M0006, M0019, or M0054VOXL, VOXL-Flight, or VOXL2Purchase links: VOXL2, VOXL-Flight, VOXL
1Ground station deviceComputer, laptop, etc. 
1Power sourcePower supply for ground station modem5V Operating Voltage
1USB-C cableUSB-C to USB on specified port on ground stationUSB-C, A, etc.
2BluSDR-6 RadioDTC BluSDR-6 radioDescription
2DTC AntennasCables, antennas 

VOXL Hardware Setup

Using M0078

Compatable boards include the USB Expansion Board with Fastboot v2 and the USB Expansion Board V1. Other hats should work as well, as long as they don’t have any other modems installed.



Pictured above for your reference is a VOXL2 flight deck with a DTC BluSDR-6 radio connected.

IMPORTANT! Before modifying hardware setup, ensure power is off or disconnected.

  • Attach M0078 add-on board to J3 of VOXL2.

  • Attach antennas to ports on BluSDR-6 radio.

  • Wire a JST accordingly to be able to plug from the 4-pin USB on the VOXL2 USB Expansion Board to the USB-2 port on the DTC radio.

  • Connect the 4-pin JST on the VOXL2 to the USB-2 port on the DTC radio.

Note: You must connect to the USB-2 port on the DTC radio, and NOT the USB-1. The USB-1 port is used for host only, while the USB-2 is used for host/peripheral. The VOXL2 dtc connection must be peripheral, so USB-2 is required.

  • Attach M0041 APM to VOXL2 and provide power

  • Provide power to the DTC radio. It must be powered through the power port shown above.

  • Plug in USB-C cable from desktop to VOXL2 in order to access ADB later on.

Ground Station Hardware Setup


Pictured above for your reference is a ground station setup showing a DTC BluSDR-6 Radio and breakout board.

IMPORTANT! Before modifying hardware setup, ensure power is off or disconnected.

  • Attach antennas to ports on DTC radio

  • Plug in ethernet to USB into USB-2 port on DTC radio

  • Plug in power cord into Power port on DTC radio and plug into outlet

  • Plug ethernet from ethernet to usb to your computer. If your computer does not have an ethernet port, you can use another ethernet to usb on your computer side.

Software Setup

Configure Radios

  • You will need to be on a Windows computer and download DTC’s Node Finder software from here.

  • After downloading the Node Finder software, run it.

  • Hit the reload button until a radio shows up. domo-device-found

  • As you can see, the IP address is This is because it is currently in DHCP mode. But you want it to have a static IP so you can access the configuration page. Right click on the radio, click Configure Network, and assign a static IP for the radio.


  • Set a static IP address for the host PC in the same subnet as what you set for the radio. As an example:


  • In a web browser, enter the IP you set for the radio on Domo Node Finder. A login screen should be brought up. Leave the username blank and enter “Eastwood” for the password. You should now be in the radio configuration screen.

  • On the left navbar, go to Presets -> Mesh Settings


  • Mesh id should be the same for all radios on the same mesh, so no need to change it.

  • Node id should be unique for each radio on a mesh network. By default is it set to 0. Set this radio’s Node id to 1.

  • Check Enable Transmitter. Set the frequency, PA linearity, and channel bandwidth to what is desired.

  • Hit the save button to save the desired settings.


  • Once you are done, turn off the radio and swap it with the one you are going to use on the VOXL2 side. Temporarily wire the VOXL2 radio to your GCS computer so you can configure it.

  • Repeat the steps above for the VOXL2 radio, making sure to match the settings. Make sure the Node ID on the VOXL2 radio is different than the Node ID on the GCS radio.

  • Also make sure to make IP address of the second radio different than the first radio.

  • On the VOXL2 radio, make sure to go to Global Setup->General Settings and set USB Mode to Peripheral. If you fail to do this, the radio will NOT show up as a USB device when connected to the VOXL2 and will never be configured.


  • After you are done configuring the settings for both the VOXL2 and host computer radios, you can plug the VOXL2 radio back to the VOXL2 and then turn both radios on and look in “Domo Node Finder” to confirm both are found. You can also look in the configuration page to see if there are multiple nodes on the mesh. Look at the Network Status to see how many active nodes there are.


VOXL2 Software Setup

  • adb onto VOXL2
adb shell

  • Run the following the begin modem setup:
voxl2:/$ voxl-configure-modem 
What type of modem are you using?

If you are unsure of which modem you have, take a look at the following datasheets:

v2 LTE Modem:
Microhard Modem:

1) v2
2) microhard
3) dtc
4) doodle
5) quectel
6) em9191
  • Select dtc from the menu
#? 3
Enter the IP address you would like to the VOXL to use on the DTC network:
Note: The chosen IP address must be of the form: 192.168.0.XXX

Default -

1) default
2) custom

  • Select the static IP you would like your VOXL2’s usb0 network interface to be set to, either choose default or another IP on the 192.168 subnet
#? 1 

Making new interface file /etc/network/interfaces

qrb5165 based device detected
reloading systemd services
enabling voxl-modem systemd service
starting voxl-modem systemd service
DONE configuring voxl-modem

  • The VOXL2 will now enable the voxl-modem service in order to enable the bluSDR radio connection and set the static IP on bootup

  • Verify that the usb0 network interface has enumerated and that the IP has been set correctly:

voxl2:/$ ifconfig usb0
usb0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1500
        inet  netmask  broadcast
        inet6 fe80::4150:d5f3:7861:747a  prefixlen 64  scopeid 0x20<link>
        ether 0a:a6:a8:f6:48:69  txqueuelen 1000  (Ethernet)
        RX packets 312  bytes 18106 (18.1 KB)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 725  bytes 65407 (65.4 KB)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

Ground Station Software Setup

  • As already shown above, you have set the Ground Station static IP address.

In this case, the IP address of the host PC was set to

Connecting to QGroundControl

Now that both the VOXL side and ground station side software have been setup you should be able to ping one device from the other.

For example, one can ping the host computer radio by doing the following (assuming the DTC radio on the host computer has the IP address of

voxl2:/$ ping
PING ( 56 data bytes
64 bytes from icmp_seq=0 ttl=64 time=48.223 ms
64 bytes from icmp_seq=1 ttl=64 time=66.942 ms
64 bytes from icmp_seq=2 ttl=64 time=63.329 ms
64 bytes from icmp_seq=3 ttl=64 time=54.784 ms
64 bytes from icmp_seq=4 ttl=64 time=43.811 ms

Or one could ping the VOXL2 from the host computer by pinging the VOXL2 IP from command prompt:


Pinging with 32 bytes of data:
Reply from bytes=32 time=29ms TTL=64
Reply from bytes=32 time=52ms TTL=64
Reply from bytes=32 time=44ms TTL=64
Reply from bytes=32 time=43ms TTL=64

Ping statistics for
    Packets: Sent = 4, Received = 4, Lost = 0 (0% loss),
Approximate round trip times in milli-seconds:
    Minimum = 29ms, Maximum = 52ms, Average = 42ms

Note: You may have difficulties pinging the host computer itself from the VOXL2. But if you can still ping the host computer radio IP from the VOXL2 and the VOXL2 IP from the host computer, you are good.

Since we are able to get packets from drone to ground station we can now connect our VOXL2 / drone to QGroundControl.

The VOXL system uses the voxl-vision-px4 service on VOXL to establish a connection between PX4 and QGroundControl over UDP. This is supported on VOXL2, VOXL Flight or when using Flight Core with VOXL.

If you have not yet setup voxl-vision-px4 on your VOXL, do the following:

# On Host PC
$ adb shell


You will be asked a variety of questions about your hardware configuration, answer these questions with the options that best describe your setup.

  • When asked for the IP address for QGroundControl, you’ll use the IP address of your ground station, in this example

If you have already configured voxl-vision-px4, you can edit the configuration file as needed. Run the following command and update the qgc_ip field to match the GCS computer’s IP, in this example

vi /etc/modalai/voxl-vision-px4.conf

	"config_file_version":	1,
	"qgc_ip":	"",
	"en_secondary_qgc":	false,
	"secondary_qgc_ip":	"",
	"qgc_udp_port_number":	14550,

If you’ve modified the config file, restart the voxl-vision-px4 service and reload the configuration by running the following command:

systemctl restart voxl-vision-px4

You should now be able to open QGroundControl and see data being passed from your drone to your ground station via the DTC radios.