Neckarcup First Challenger On Clay To Use Live Electronic Line Calling

Javier Simon (photo:

HEILBRONN, June 8, 2024

“Out” – “Fault” – “Foot Fault.”

Regular visitors to the NECKARCUP might be surprised this year to hear these calls sounding a bit more metallic. And where have the line judges gone?

This year, the usual human line judges have been replaced by the FOXTENN Electronic Live Calling system. The NECKARCUP was selected by FOXTENN as the first ATP Challenger Tour tournament and the first clay-court men’s event worldwide to work with the system of the Spanish high-tech company.


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On the sixth day of the tournament’s 10th edition, FOXTENN founder and CEO Javier Simon took the time to discuss the experiences from the first days in Heilbronn.

Tennis TourTalk: Javier, how have the first days of the NECKARCUP gone for you?

Javier Simon: We are very satisfied with how it’s going. We have now completed around 50 matches and analyzed over 10,000 situations where the ball landed close to the line. The chair umpires, the ATP supervisor, and the tournament organizers are happy. So, we are, too.

What distinguishes your system from others?

FOXTENN is the only system that is 100 per cent based on real captured images, while all other systems rely on estimations, such as the ball’s trajectory, and therefore cannot achieve 100 per cent accuracy.

How does the system work? The balls come so fast that the human eye can hardly tell if a ball lands on or off the line.

We have installed 42 high-speed cameras here which, combined with 10 laser scanners, capture 3,000 images per second. In contrast, the human eye captures only 25 images per second. This means we can accurately analyze the moment the ball touches the ground and provide video evidence of whether it was in or out.

You not only have a lot of technology at the NECKARCUP but also about 12 people working in a dedicated room in the tennis hall. What happens behind the scenes?

For each court in play, we have three work stations. So, in the first days when matches were happening on all three courts, nine of our people were working simultaneously. One person is responsible for the laser measurement, another for the functionality of the cameras. The third is the contact person for the ATP official, who is also with us during the matches and communicates with the chair umpires. When a player requests a review, communication needs to be instant.

Your system can do much more than what you are showing at the NECKARCUP.

Since the FOXTENN system is so accurate, we can also analyze and evaluate the match itself. The statistics we gather can provide valuable insights for TV broadcasts, the ATP, and the players themselves.

Finally, as someone who travels a lot on the tour, how do you like the NECKARCUP?

I have been to many Challenger tournaments, but the NECKARCUP is undoubtedly one of the best in the world. The organization is professional, yet everything feels very familial. We feel very comfortable at the NECKARCUP.

Thank you.

Interview: Florian Heer and Ralf Scherlinzky