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 2020-01-01. You need the corresponding 2020-01-01 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 for baseline

When the Line Device boots, a "Please Wait" screen is shown.


During the first 5 boots, an information screen is shown:


On the preview screen, align the device with the baseline and press the button that points towards the net.

ld-preview.jpg ld-linecall0.jpg

Software for sideline

It's possible to use the Line Device on a sideline.

When the "Please Wait" screen is shown, press any button. At the next boot, you will be presented with the advanced "Please Wait" screen.

ld-wait.jpg ld-wait2.jpg

The device will ask you if it should be configured as baseline or sideline. Press the relevant side button.


For sideline, the device will ask you if the device is located around the net or in the back of the court against the fence. Press the relevant side button.


On the preview screen, align the device with the sideline and press the button that points towards the middle of the court.

ld-preview2.jpg ld-linecall2.jpg ld-linecall6.jpg

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.


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.


Line Device firmware upgrade

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

Tools Flash Normal

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.

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

There are two modes to flash 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.

Flash Forcing