Available circuits filled up quickly in Boston. When cell phones can't get through they encounter fast busy signals or automated messages, Lipoff said. A rumor circulated that cell service was cut to prevent a bomb from being detonated by cell phone. Wireless carriers later issued statements disputing that report but did say the heavy call volume overwhelmed their towers.
Instead of calling, the carriers recommended their users try communicating via text or email from their phones. While this may seem counter-intuitive, voice communications do require a constant connection. Email messages, however, travel by packet switching. In the short time between one phone call and another, you could send a thousand email messages, Lipoff said.
When wireless companies have time to plan for a surge, they can increase capacity. Lipoff pointed to the annual Consumer Electronics Show in Las Vegas, where cellular base stations were added to make dozens of little cell sites at the convention center. After natural disasters like Hurricane Sandy, quick deployment sites were also brought in on trucks.