See STOP, HOLD and SLOW on a phone for crane operators

What you need before you start

To see the ground crew's STOP, HOLD and SLOW on a phone, the operator needs a phone with a working browser and a data signal, because the signals travel over the phone network. ^[1] The person who starts the jobsite needs to share a link or QR code, and the rest of the crew joins from it. ^[1] If everyone leaves the session and it sits empty, it is wiped after 3 idle hours, so a stopped-shift session may need to be started fresh. ^[1] Decide whose phone is the one that shows HOLD and SLOW, because those two signals stay on for everyone until the last person leaves the jobsite. ^[1] Before the lift, add the page to the phone's home screen so it opens as a standalone app. ^[1]

Step by step

1. Check each phone has a working browser and a data signal for the whole shift, because the signals pass between phones in a browser. ^[1]
2. Have the person who starts the jobsite open the session from a phone browser, with no app install needed. ^[1]
3. That person shares the link or QR code with the ground crew, and each member joins from it. ^[1]
4. Confirm every crew member is in the session before the lift begins, so each one sees the same signals. ^[1]
5. Agree on which signals stay on: HOLD and SLOW stay on for everyone in the jobsite and are cleared only when the last person leaves. ^[1]
6. Pressing a move button keeps sending that move to the other phones, and if it stops arriving for 2 seconds, the other phones drop it, so keep the button held while checking the load. ^[1]
7. When STOP is pressed, it releases every held direction on every phone and shows a full-screen alert to everyone else, so pause and look before moving again. ^[1]
8. At the end of the shift, everyone leaves the session, and remember that a jobsite with nobody in it is wiped after 3 idle hours. ^[1]

Tools that can do it

OperatorLink is made by the team that publishes this site. It shows STOP, HOLD and SLOW to the jobsite crew and passes button presses, chat and voice between phones in a phone browser. ^{[1] [1]} Nobody needs to install an app; the page runs in a browser. ^[1] The person who starts a jobsite shares a link or QR code, and the crew joins from it. ^[1]

A phone video call app is a second option. No facts here describe one, so check whether the crew can keep the call open for the whole shift, whether the signal person's hands stay in view, and whether the phone locks its screen mid-lift.

A two-way radio is a third option. No facts here describe one, so check that the crew agrees on plain voice, that every member can be heard over machine noise, and that the channel stays clear through the lift.

Match the option to the crew and the site, and keep a fallback ready since signals in a browser depend on the phone's data signal.

Common mistakes to avoid

Relying on one phone for the STOP signal: if that phone's data signal drops, the rest of the crew does not see it, so keep a voice or hand option ready. Assuming every phone alerts the same way: on Android browsers, signals such as STOP make the phone buzz, while iPhone Safari ignores the buzz, so check the sound and screen on every device. ^[1] Leaving an empty session and expecting it to hold signals the next day: a jobsite with nobody in it is wiped after 3 idle hours. ^[1] Forgetting that HOLD and SLOW stay on for everyone until the last person leaves, so the crew has to clear them on purpose. ^[1] Not confirming that a move still arrives: if a move stops arriving for 2 seconds, the other phones drop it. ^[1] Letting the phone go to sleep mid-lift; adding the page to the home screen as a standalone app helps the screen stay available. ^[1]

Frequently asked questions

Is OperatorLink free to use?

OperatorLink is currently free to use, and no paid plan is built yet. ^[1] The signal is shown through a phone browser, so the phone still needs a working data signal for the shift. Check the phone's data plan before relying on it.

What happens when the STOP button is pressed?

STOP releases every held direction on every phone in the session and shows a full-screen alert to everyone else, so the crew sees it at once. HOLD and SLOW behave differently: they stay on for everyone until the last person leaves the jobsite.

How long does a jobsite link stay active?

A jobsite link stops working 12 hours after the first person joins it, so a link from an earlier shift may no longer open the session. A jobsite with nobody in it is wiped after 3 idle hours. For a fresh shift, start a new session and share the new link or QR code with the crew.

Do STOP signals buzz on every phone?

On Android browsers, signals such as STOP make the phone buzz. iPhone Safari ignores the buzz, so on an iPhone the alert may only be seen on screen. Check the sound and screen settings on every phone in the crew before the lift so nobody misses the signal.

Can crew members talk over the phone during a lift?

Anyone who joins the jobsite can take part in a voice call run from the phone browser, and one-tap radio-style calls such as Go Ahead, Copy That and All Clear are sent as chat messages. Voice depends on the phone's data signal, so keep a radio or hand signal as a fallback.

Sources

1. OperatorLink's own description of itself (the product of this site's publisher)

Related comparisons

• How to get the whole crew onto one jobsite link
• Send STOP, HOLD and SLOW to the operator from a phone
• How Crane Operators Talk to the Signal Person in 2026
• Crane communication headsets compared
• Crane communication headsets for operators
• Crane communication headsets for signal persons and riggers
• Push-to-talk apps for crane crews compared (2026)
• Best push-to-talk apps for crane operators in 2026
• Push-to-talk apps for crane signal persons and riggers
• Crewplex alternatives in 2026: 6 options