Unbeknownst to the public, advertising signals have been placed in phones booths throughout the five boroughs that may eventually send smartphone users coupons and other notifications.

Buzzfeed News has released a report on hundreds of beacon signaling devices that have been installed in New York City telephone booths.

While only in the testing phase, the New York City public was given no notification that this was happening.

These devices send data via Bluetooth low-energy radio signal to smartphones that have an app with permission to receive the notifications.

Already in use in other locations such as sports stadiums, beacons are used to send information, coupons or current deals at nearby retailers to the phone any time it’s in close proximity to the device.

The outdoor media company, Titan, is behind the installation of around 500 beacons in phone booths throughout the city.

It's unconfirmed what precisely these beacons will be used for in the future, but its possible data from a passerby's phone could be recorded if the user has provided permission to the retailer to send marketing information.

This form of hidden commercialization adds to the surveillance already in place from security cameras and cell phone towers.

If the beacons make it out of the testing phase, a formal approval will be required from the city.

According to Doug Thompson, the CEO of beacon technology company dot3, “Consumers should be aware when they’re in a zone that projects beacons."

While no specific locations were revealed, Buzzfeed News reports the largest congregation of devices appears to be in central and lower Manhattan.

The news organization used Android app iBeacon detector to find this out. Any Android user can download the app to locate nearby beacons.