When my cell phone rang at 4:28 a.m. on Aug. 2, I immediately thought it was an emergency. And it was, sort of. The federal government had raised the terrorism threat level to "orange" in Washington, New York and northern New Jersey. Problem was, the news had broken on Aug. 1.

For more than a year I've been testing a version of a new service rolled out officially to D.C. residents in July in which alerts -- not just about terrorism, but weather, exploding manhole covers and traffic problems -- are sent by text messages to mobile phones and e-mail accounts. Like most everything related to homeland security, a cottage industry has emerged around developing a modern emergency broadcasting system.

Washington is the first major city to offer text alert service free to residents, and its system illustrates both the promise and problems of terror alert technology, which is in early stages.

Messages can reach people quickly, direct them away from danger or warn them of other problems. But the messages must be short. It took three separate ones to tell me about the orange alert. More strangely, the first two arrived at 4:28 a.m. and the third at 12:04 p.m.

Ned Ingraham, senior manager of information technology for D.C.'s Emergency Management Agency, says the glitch, which sent messages many hours after the alert was heightened, was the government's fault. "We had some internal problems with the software," he said, but he declined to elaborate.

Daniel Gadra, vice president and general counsel at Roam Secure Inc., a 10-person Arlington company that developed the system, downplayed the problem, saying it was easily fixed. He said that when jurisdictions first roll out such systems, there are often little snags, but they are usually quickly worked out.

There were two problems, according to a source familiar with the situation who did not want to be identified because he does work with the District. No one pushed the send button until several hours after the announcement, and then a virus protection system that scans outgoing messages held up the alert.

Ingraham says he's "99.8 percent certain" the problem has been eliminated. So far, 3,200 people have signed up for the D.C. system at www.dc.gov.

Meanwhile city officials are working with representatives of Washington suburbs to connect their separate text messaging system, Ingraham said. (Roam Secure has developed systems for Arlington and Fairfax counties, as well as one soon to be launched in Montgomery County.)

A handful of companies are competing with Roam Secure for this market. One, AlertsUSA in Nashville, lets customers press a phone button to hear additional information through an audio stream. Users of Nextel mobile phone services can choose from a menu of alerts, including a personal "homeland security" team from AlertsUSA, weather updates from The Weather Channel and breaking news from CNN.com.

Ingraham said his office considered hiring AlertsUSA to build the District's system, but concluded that the audio service mispronounced too many names and places, which would spread confusion.

Robert Hammond, director of business development at AlertsUSA, said while most text-to-speech technology does have pronunciation problems, such issues are very rare at his company because AlertsUSA uses a human rather than a synthetic voice.

AlertsUSA's president, Steven Aukstakalnis, said he thinks the bigger problem is with text-only alerts, which must be compressed into a small number of characters. He says both intonation of audio alerts and wording of text alerts need to be carefully thought out. "You can scare the bejeesus out of somebody," he said, with incorrect phrasing or emphasis.

Aukstakalnis said that in contrast to Roam Secure, which is going after government or business customers with its customized software, AlertsUSA targets individuals, charging a monthly fee for its one-size-fits-all system. He said it has tens of thousands of customers.

Intelligent Wireless Solutions in Houston, which sends text and audio alerts over mobile phones, pagers and e-mail, has been providing a variety of private emergency broadcasting services since 1986. Its customers include energy companies and oil refineries, which need to communicate quickly about spills and missing inventory, according to company President Jerry McMullin. Recent events, such as terrorism and school violence, prompted the firm to offer systems for businesses, federal agencies and educational organizations. Its "schoolwarn.net" program, for example, provides an alert system for teachers and parents on school closings, weather and shootings.

McMullin said he favors audio alerts over text messages, because e-mail systems are often unreliable. But he said it is difficult to plan for every contingency. The company operated an internal alert system for the World Trade Center. But when the buildings' phone service went down quickly after the Sept. 11, 2001, attacks, the system was useless, he said.

Gadra, however, said that despite the occasional glitches, the systems generally do what they are supposed to.

As I was finishing this column yesterday at 4:10 p.m. it started pouring outside my office. At 4:14 p.m., my phone rang and new e-mail dropped into my box telling me there was a severe thunderstorm warning for the District and surrounding areas. The timing was better, although I would have been even more impressed if the message had reached me before the storm hit my neighborhood.

Shannon Henry writes about Washington's technology culture every other Thursday. Her e-mail address is henrys@washpost.com.