Cable operators and other distributors that offer voice-over-Internet-protocol phone service will have until Sept. 28 to notify subscribers that E911 may not always work on their systems, according to a Federal Communications Commission ruling Friday.

The agency decided to give VoIP providers an additional 30 days before enforcing an FCC requirement that the providers obtain “affirmative acknowledgements from 100% of their subscribers that they have read and understood an advisory concerning the limitations of their E911 service,” the FCC wrote in a public notice Friday.

The ruling will impact firms like Vonage Holdings Corp., which sell VoIP service to cable-modem and digital-subscriber-line customers, and MSOs that offer their own VoIP service, including Time Warner Cable and Cablevision Systems Corp.



On July 29, the FCC ruled that VoIP providers must advise new and existing customers about circumstances in which E911 service may not be available and obtain records showing that each subscriber understood the limitations.

The FCC also ruled that VoIP providers must distribute warning stickers to their customers explaining that E911 service may be limited or unavailable.