Inside the Hidden World of Elevator Phone Phreaking | WIRED
Aditi Chansoria on Twitter: "Hello @IKEAIndia @ikeaindiastore Incredible store! Just not sure whom to call for emergency at 7:56 pm. #ikeahyd #IKEA https://t.co/3I93bSrXJm" / Twitter
Emergency Communications System Requirements for Elevators