Business

Cellphone networks overwhelmed after blasts in Boston

MIT professor says outage highlights need for upgrades so calls can go through during disasters

Cellphone signal strength of major carriers in the Back Bay on Tuesday:

Best
Good
Poor
No data

AT&T

Sprint

T-Mobile

Verizon Wireless

SOURCE: RootMetrics

Patrick Garvin/Globe Staff

Real journalists. Real journalism. Subscribe to The Boston Globe today.