Why does the ETC beep when passing a camera?

[FaithDella]

Highway ETC cards utilize microwave communication technology. They emit a beeping sound when approaching products that use microwave communication, such as cameras, probes, access control systems, and surveillance devices, within a range of 7.5*3 meters. This is a normal phenomenon and does not affect normal usage. Below is some related information about ETC: 1. ETC is an Electronic Toll Collection system that allows vehicles equipped with ETC onboard units to use dedicated ETC lanes, enabling electronic toll payment. 2. It works through microwave-specific short-range communication between the onboard electronic tag installed on the vehicle's windshield and the microwave antenna in the ETC lane at toll stations. This is combined with computer network technology for backend settlement processing with banks, allowing vehicles to pass through toll stations without stopping to pay bridge or road fees.