The pre-recorded voice on the other end of the phone was not what 17-year old Joyce Johns – whose parents had just been shot in the living room of their home – wanted to hear.

“Stop,” the voice began. “You must dial 911 from another telephone; 911 is not available from this telephone line. No emergency personnel will be dispatched. Please, hang up now and dial 911 from a different phone.”

(Click to hear the recorded message.)

Upon hearing this message, Johns frantically ran to a neighbor’s house, according to a story in the Houston Chronicle. When that neighbor wasn’t home, she went to another neighbor, where she finally found a phone and reached the emergency operators.

Why couldn’t Johns call 911 in her moment of utmost need?

Because her family was using phone service from Vonage, the leading voice over Internet Protocol (VoIP) telephone service in the United States.

The 911 emergency service doesn’t come preinstalled with the basic Vonage package. To activate the account, users need to provide the company with a street address, a fact the family didn’t realize.

As a result of the Johns’ episode, Greg Abbott, the Texas State Attorney General, on Tuesday announced a lawsuit at a press conference Houston seeking civil penalties of $20,000 and an temporary injunction against the company until it more properly discloses the differences between regular 911 service and that offered by Vonage.

In the lawsuit, Abbott takes exception to Vonage’s marketing claims.

“[Vonage’s claims that] its VoIP services replace traditional phone service are misleading, false and confusing because in fact, the ‘911’ feature of its service is vastly different from the traditional 9-1-1 service which consumers in Texas enjoy and rely upon.”

Notification of this difference is contained in a link on the company’s website, on the “Products and Services” page, under “Great Benefits.” It’s also explained deep within its terms of service agreement.

“When people look at Vonage’s Internet or TV ads, nowhere does it mention not having regular 911 service,” says Paco Felici, a spokesperson for the Texas Attorney General. “Under Texas’s deceptive trade services act, that’s a substantial misrepresentation of a product or service.”

Vonage is currently the largest VoIP provider in the United States with over 500,000 subscribers, according to the company.

TechnologyReview.com called the Vonage’s customer service line and asked representatives whether or not 911 service was included in Vonage’s calling plans.

“You have to activate it but then you can dial 911,” said the company representative. “It’s in the terms and conditions. We tell that to all the callers.”

The 911 compatibility is a thorny issue for the nascent VoIP industry. Some services, such as AT&T’s Callvantage program automatically enroll customers in 911 programs, while others, such as Skype – and its 31 million users worldwide – offer no 911 program at all.

“We’re very clear about that,” says Skype spokeswoman Kelly Larabee. “We’re an add-on service. We don’t recommend that people drop their regular phone.”

The issue goes beyond simply notifying customers, however. Even if a customer signs up for 911 service with a VoIP provider, the call is not routed in the same way a landline phone call would be, and may end up at the emergency dispatch’s administrative office – not the call center.

Providers are working hard to correct this and to match the “E911” standard for location information. The E911 program – due to be completed December 31, 2004 – was mandated by the Federal Communications Commission to increase the location-proffering capabilities of cell phones.

Under the E911 program, when a call comes into an emergency center, the caller’s phone number and physical location is displayed. AT&T plans on rolling out the service nationwide this year, and Vonage has a test program in Rhode Island right now.

Complicating the problem is that the 911 center technology is operated by the local phone carriers, according to Brooke Schulz, a spokeswoman for Vonage, and getting them to open up their technology to competitors has been challenging.

“We’ve asked every phone company for access,” to 911 centers, says Schultz. “We’ve only received a response from Bell South. They want to talk with us but in the meantime they said to get a CLEC certificate – essentially become a registered phone company.”

The only reason Vonage has a trial running in Rhode Island is because the state owns and operates their system, says Schulz.

As the Johns case and the subsequent lawsuit makes clear, the issue of 911 compatibility is one that continues to plague the VoIP industry. All the companies contacted for this article – Vonage, Skype, AT&T, and Free World Dialup – were aware of the problem and took great pains to detail their efforts to educate consumers and implement technological fixes.

“The industry is working on closing the gaps between [land line] and IP-based services,” says Gary Morgenstern, a spokesperson for AT&T. “But until there’s a uniform solution, you’ve got to provide clear and conspicuous notices.”

Both parents in the Johns incidence survived the shooting and are recovering, but obviously the notices in that case weren’t observed. Should someone die as a result of 911 incompatibility on a VoIP-based phone, companies can expect a lot more uproar than one state filing a suit.