Imagine it's midnight and fire sirens are wailing around your home.
If you're outside watching smoke pour out of your windows, you're happy that help is on the way.
But if your house isn't on fire and you -- and your spouse, your children and your dog -- are sound asleep, that siren is less of a comfort and more of an annoyance.
For most Western Pennsylvanians, fire sirens have been part of the soundtrack of everyday life for decades. But with advances in technology from pagers to smartphones, are they still necessary?
The answer to that question depends on whom you ask.
For all-volunteer departments such as the Perrysville Volunteer Fire Co. in Ross, the siren is the best way to make sure firefighters know there's an emergency, according to fire Chief Eric Wissner.
Plus, he said, residents like to know what's going on.
"We've heard from many residents that work and also live in the area -- they kind of like it because when the siren goes off, they know there's an emergency somewhere," he said.
The company responded to about 200 calls last year, and Chief Wissner said no residents have lobbied to silence the siren.
On the contrary, he said: "I think there would be some people against getting rid of it."
But the story is completely different at the all-volunteer fire department in North Fayette, which responded to more than 400 fire and other emergency calls last year.
Fire Chief Gary Hamilton said the department still has a siren but hasn't used it for fire calls in more than 15 years, "basically due to pressure from the community."
"I think the people who still think that [sirens] are needed, I think it's probably a nostalgia thing," Chief Hamilton said, noting that he works outside North Fayette and wouldn't hear a siren when he's at work anyway.
"In this day in age, with all the technology that we have, I think people want to cling to that tried-and-true 'when the whistle blows, the firefighters come running,' " he said.
All of North Fayette's roughly 35 volunteers carry radio pagers that alert firefighters when there's a call.
"That's the first line of defense," Chief Hamilton said.
Then, a notification is sent to a Web-based system called I Am Responding, which sends text messages and emails to volunteers via www.iamresponding.com.
Chief Hamilton said all of these alerts actually happen simultaneously. Firefighters then respond to an 800 number to indicate they received the notification and are headed to the site of the emergency. Some can pull up the system on their smartphones to see how many firefighters are responding before they even get to the scene.
"It's been a big advantage for us," Chief Hamilton said.
The system costs the department about $800 a year, but Chief Hamilton said, "it's more than worth its weight in what it's done for us."
Prior to adopting the online system, the department relied on only the radio pagers, which sometimes didn't activate properly.
"I might actually get my text message to know I have a fire call before my pager goes off," the chief said.
Bad pager service is just one reason some communities keep their sirens in working order, according to James Marcoz, owner of J. Marcoz Emergency Vehicle in North Versailles. He said he repairs three or four sirens a month, largely in communities that don't have good coverage with their paging systems.
"Most of the communities that keep them running do have a need for it," he said.
Fire departments in Mt. Lebanon and Jeannette are siren-free, largely because both have at least some paid firefighters. Mt. Lebanon has 17 full-timers and 45 volunteers to respond to calls, according to fire Chief Nick Sohyda. A tone goes off in the station to alert the paid firefighters, who staff the station day and night, and volunteers are notified via pager.
Chief Sohyda said the last time the municipality used a siren was in the 1980s, although the town has a tornado siren that is tested once a month.
J.C. Tedorski, secretary of the Western Pennsylvania Firemen's Association and fire chief in Arnold, said he's seen a shift in the use of sirens as new technologies move in.
"The fire siren is more of a community warning device than it is to warn firefighters anymore," he said.
"Let's say that we have -- God forbid -- an impending tornado," Chief Tedorski said. "If we put that fire siren into one single long blast that goes on for two minutes, doesn't cycle up and down, people are going to say, 'That's not normal. There's something going on.' It truly is community alerting."
He said that some towns have moved to using sirens only to alert youths that a curfew has begun or in disaster situations such as tornadoes. But in small towns, he said, the fire siren acts as "first-level feedback" that someone is coming to help.
Jeannette, which has seen a series of arsons in the past 11 months, relies exclusively on paid firefighters -- three full-timers and 29 part-timers. The city doesn't use a siren because firefighters are always in the station, Chief Joe Matijevic said.
Firefighters are dispatched via Westmoreland County 911 and notified in three ways: bells ring at the station, radio pagers called Minitors that are clipped to belts alert the firefighters, and cell phones buzz with emails and texts.
Additionally, firefighters with smartphones can download a dispatch app, which can give the firefighter a map of the location of the fire and soon will be able to direct firefighters to nearby hydrants.
The National Fire Protection Association recommends at least two means of dispatching firefighters, and sirens now are largely used as the backup notification, according to Ken Willette, division manager of the public fire protection division of the NFPA.
He said he's heard arguments for and against the use of sirens. He noted that sirens are becoming expensive to repair, and some residents find them annoying. On the other hand, Web-based alerting systems depend on the Internet and electricity, so if power goes out, alerting first responders could be an issue.
But for day-to-day emergency calls?
"The technology is at its finest as far as dispatch notifications," Chief Matijevic said. "It just keeps getting better."
Annie Siebert: email@example.com or 412-263-1613. Twitter: @AnnieSiebert.