Less than a month after experiencing problems with alerts sent after false reports of gunshots fired on campus, Virginia Tech successfully tested its emergency alert system Monday.

Tech spokesman Mark Owczarski said more than 70,000 test messages went out to more than 35,000 subscribers in about half an hour, beginning at 1:35 p.m.

The alerts that caused problems in November -- Tech's VT Alerts system delivered by California-based emergency notification company 3n -- were delivered without a problem.

"From what we can tell on our end and from what 3n is telling us, the message was delivered to all of our subscribers," he said.

On Nov. 13, sounds that people reported as possible gunshots fired in Tech's Pritchard Hall turned out to be caused by the explosion of a nail gun cartridge.

But the emergency, which shut the residence hall down for two hours, revealed problems with the text message, voice message and off-campus e-mail alerts operated by 3n.

Only some subscribers received the first notification intended to alert campus of the shots fired, and no subscribers received two subsequent messages reporting that the sounds were not caused by gunshots.

Witnesses reported seeing two men running from the scene of the cartridge explosion in November. The university released a description of the men, and police would like to question them about the incident.

As of Monday, the case was still open and police had no leads, Owczarski said.

Electronic banner displays in classrooms, campus e-mails and a message on the university home page all worked during November's false alarm. Those systems were successfully tested Monday as well, though the test was scheduled because of the VT Alerts failure.

Owczarski said the specifics behind the November failure were still unclear, and 3n officials described the problem as a "system hiccup."

There was one small glitch detected in the voice alerts sent out as part of VT Alerts on Monday, Owczarski said. The voice synthesizer used to translate written messages to leave voice messages on phones translated "VT Alerts" into "Vermont Alerts."