Wireless PA systems are often used at truck scales for one-way communication to a truck driver. An operator in the scale house can simply press a button and broadcast a message to the driver. These systems can broadcast at high volume levels so they can overcome the noise level of a loud diesel engine.
The PA system consists of a wireless receiver unit that’s attached to a horn speaker. In the scale house the operator an use a portable handheld radio or a desktop base station radio to broadcast messages to the trucks.