"The survey reinforces that interoperability is achievable," Chertoff said in a statement. "That technology works today and is available. The willingness of emergency response leaders and local officials to make this issue their priority is what will continue to drive progress on one of 9/11's most important lessons."

Chertoff's office was asked repeatedly to react to the Democrats' concerns, but a spokesman could not be reached for comment.

Lowey is sponsoring a bill that would require the DHS to develop a national strategy for interoperability and that calls for a $5 billion fund to pay for new interoperable technology for first responders, an aide said.

Craig Mathias, a wireless industry analyst at Farpoint Group in Ashland, Mass., said the survey result showing some level of interoperability in use by two-thirds of the respondents is encouraging. "The effort has been a fairly recent one, starting with 9/11, and a good deal of consciousness-raising has occurred," he said. "Some cities and regions have taken on the problem to work among themselves."

But Mathias also said that nationwide interoperability is "still an immense problem ... that will take decades" to achieve. "Twenty years is not an unreasonable amount of time to expect for true interoperability ... where a firefighter is patched through to talk to a doctor in a hospital."