Line Device

This page has the latest up-to-date information about the Line Device. First, there is a quick setup guide for the Line Device in pdf format for the Line Device.

The Line Devices assists the Net Device(s) the same way the line umpires assist the chair umpire. It provides better accuracy to the In/Out system. The calls are still made and decided by the Net Device(s). The Net Device "inputs" the information sent by the Line Device.

The latest version of the Line Device firmware is 2019-11-11. You need the corresponding 2019-11-11 Net Device firmware, available here in order to flash the Line Device with the latest version. Read the last section "Firmware upgrade" at the bottom of this page for more information.


The Line Device is composed of only one piece. It has an ON/OFF slide button and two side buttons to navigate the UI. There is no touchscreen.

Line Device

At the bottom of the device, the pads can be rotated to get better stability especially in windy conditions.

A couple of enhancements has been recently added to improve the Line Device hardware:

Software on the Net Device

The Line Device screen is accessible from the Settings->Advanced screen. It's only functional on a version 2.0 Net Device (green device).


There are two actions possible on the Line Device screen:

This Side Other Side

Important Requirement: The two Line Devices need to be placed against the same fence. The Net Device need to know if the Line Devices are close or far from it. Therefore, you need to indicate the location of the Line Devices on the Net Device.

Note: If you have two paired Net Devices, changing the location will update automatically the other Net Device. You don't need to cross the court to put the opposite setting on the other Net Device.

Independent calls for testing

It's now possible to put the Line Device in an independent call mode, meaning that the Net Device doesn't need to see the ball bounce in order to include the call information sent by the Line Device. This could be useful if you want to test and better understand how the Line Device works. Start the Net Device and to go the Line Device screen. Remain on this screen.

This Side

When the Line Device will catch a ball, the Net Device will beep once for a ball IN, multiple times for a ball OUT.

Test Line

Calls reported on the Net Device

When a call is detected, the line calling screen of the Net Device will show if the call has been made by the Line Device. More precisely, it's indicated if the call is confirmed or overruled by the Line Device. To add more clarity, when (and only if) the Net Device detects a ball AND the Line Device detects the same ball, the Line Device call "WINS" over whatever the Net Device saw. Therefore, the Net Device always makes the final call which could have been either confirmed or overruled by the Line Device.


In the Settings->Signal screen, it's possible to select "Line Call" to trigger light and/or sound only when the call has been confirmed or overruled by the Line Device.


Known issue

The camera preview might take a few seconds to appear on screen. Just wait, it will appear or reboot the Line Device if you are too impatient.

Firmware upgrade info

The firmware of the Line Device needs to be upgraded via the Net Device. Use the yellow USB cable (or any other micro USB cable) to connect the Line Device (micro USB port) to a version 2.0 Net Device (USB female port). Select "Firmware" in the Line Device screen.

There are two modes of flashing of the Line Device: "Normal flash" and "Forcing flash". In the default normal flash, the Net Device gets information back from the Line Device to know if the flashing process is OK or not. For instance, the flashing won't happen if there is no Line Device or if the Line Device is not in upgrade mode or disconnected. In the "Forcing flash" mode, the Net Device doesn't care about the Line Device and forcingly sends the firmware.

By default, upgrade happens in "Normal flash" mode. To use the "Forcing flash" mode, press long the button "firmware" on the screen of the Net Device.

Flash Upgrade

Important Requirement: Make sure to place the Line Device in upgrade mode. Slide the ON/OFF button while pressing the opposite side button. Release the button. The screen of the Line Device should be full white.

Upgrade mode

Firmware upgrade procedure

To flash the Line Device with the latest firmware, do the following:

If the flashing procedure is not successful, you can try the following by order of importance: