Here is a sentence from an article of Economist: "No religious symbols or Hebrew script identify its exterior. Visitors must be buzzed by a receptionist into a vestibule through double doors."
I checked "buzz" in the ED, but the meaning of "be buzzed" still confused me, does that mean visitors must accept inspection of the receptionist? I have no idea...
"Buzz" in this case refers to the "buzzing sound" that electronic locks make when you push the button to open the lock. "To buzz" means to push that button, and "to be buzzed" means that someone else is pushing the button for you. "Buzz in" means to walk through the door that is buzzing because of the electronic lock.
The article is saying that the building is secretive and has a lot of security. It doesn't have labels telling people what the building is. When you come inside, you can't walk around freely; you must talk to a receptionist, and can enter only if the receptionist allows you to. The receptionist must "buzz you in", and so you must "be buzzed in".
I think that the phrase states that you can not enter freely to the building being described. The recepcionist have to push a buzzer that opens the doors.
According to the Cambridge Dictionary
to press a buzzer in order to get someone's attention
an electronic device that makes a buzzing sound:
I pressed the buzzer and after a while someone came to the door.
