The National Emergency Number Association said that public-safety answering points that are compliant with the FCC's Phase 2 mandate now serve 42.7% of counties in the U.S., in which about two-thirds of the population resides.

Just over half, or 53.9%, of the country's PSAPs are Phase 2 compliant. Phase 2 requires wireless carriers and PSAPs to provide location information for 911 calls made from wireless handsets.

In addition, NENA announced the publication of its i2 standard, which is designed to let voice-over-IP (VoIP) providers route emergency calls through the legacy E911 system.

NENA officials described i2 as an “interim solution” that lets VoIP providers offer E911 without requiring changes by the PSAP. As a result, i2 requires VoIP providers to secure access to the selective router — typically owned by an incumbent phone carrier — as the FCC's E911 order dictates.

To date, VoIP providers typically have been able to provide PSAPs with caller-location information for users that are fixed or remain in one place. VoIP providers with nomadic and mobile users have had difficulty meeting the FCC regulations.