At the same time, when the emergency button is pushed, the new radios are supposed to automatically open the microphone to all radios for 10 seconds so anyone listening could hear what was going on.
"This is Ladder 24. I'm on the second-floor back bedroom. I'm trapped! I'm in deep trouble!"
An alarm on his air tank sounded. Phipps had a five-minute supply of oxygen. He hit the emergency button a second time. He began feeling dizzy.
When he collapsed, another alarm on the air tank sounded - this one a screeching signal that notified everyone within earshot that a firefighter was down. A firefighter on the first floor came to his rescue.
According to a computer log of the data handled that night by dispatchers, there was one entry of an emergency signal from Phipps' radio - not the two that he said he sent.
Ayers said the Fire Department would review the radio transcripts from that night to see what might have been communicated by Phipps.
He said an official critique of the fire last spring uncovered no radio problems.
On Sept. 10, however, Motorola notified the Fire Department that the open-microphone feature for the emergency button might not always work.
Ayers said that in Phipps' case, "no one can tell me whether it opened or didn't open. It's something I'm pressing for right now."
Motorola also has advised the department that the radios are designed to send encrypted messages. But if a user inadvertently toggles to a "clear" setting, the radio won't transmit a message. Instead, it would send a blocked signal that sounds like a "bonk."
John McFadden, a Motorola sales vice president, said he was not aware of any complaints about the radios from firefighters.
"Most departments have their own internal investigative process," McFadden said. "Very rarely do they let the vendor know unless there's something wrong with the system."
Phipps, of Wynnefield, has returned to light duty, working at the Fireman's Hall museum in Old City. Since his accident, he can't stop himself from asking his colleagues whether they heard him that night.
"Some said they didn't hear me," Phipps said. "Some said it came out garbled. And that's like not hearing it at all."