A red button flashes on the emergency console, a loud beep sounds and overhead lights blink.

"Listen up," Private Jim Resnick of the Bethesda-Chevy Chase Volunteer Rescue Squad tells the tree children at his side.

Over the P.A. system at the headquarters we hear:

Sears store, Montgomery Mall. Lower level. Injured person. Rescue 41 respond. 10:36.

Resnick counts emphatically to five and stops. "Rescue 41 is probably on the road right now heading for Sears," he says.

"Where is it? Where's the siren?" come the questions. The kids strain to see out the dispatcher's window into the apparatus room, until Resnick explains that the ambulance taking this call will come from Bethesda fire station on Democracy Boulevard.

"Know what? I burned my legs last summer," my five-year-old says. "On hot charcoal. But we were in Greece and no ambulance came."

Private Resnick nods. I've told him that that's why the kids and I are here this moring -- to ease Dimitri's disappointment at not having been properly transported in his hour of need.

I expect the boy to display his scars, but he turns to ogle the dispatcher's console of buttons and switches worthy of Starship Enterprise. We have been told by our guide that all 911 calls from Montgomery County feed into this system from the Emergency Operations Center in Rockville. A dispatcher on round-the-clock duty monitors the radio and phone hook-ups.

"I see his bed," my son's friend says, pointing behind us.

"Mom, look at all the bottons on that phone.

There are no fewer than 30. Resnick explains that they're the dispatcher's hotlines to police and fire departments and hospitals throughout Montgomery County and the District. Communications, he says, play as big a part in rescue operations as emergency apparatus. The Bethesda-Chevy Chase squad and its neighbor in Wheaton are proud of their modern facilities and welcome the public to tour and learn about them first-hand.

Many of the rescue volunteers are students. Resnick -- who has been a squad member for four years -- is a senior at the University of Maryland.

"Do you get many visitors?" I ask him later.

"Yes. Brownie and Scout troops and a lot of families -- like yours," he tells me while my kids admire the pressurized sliding pole leading down from the second floor bunk room. Jim has shown us the lobby, where a blood-pressure cuff stands available for community use; the lounge; the game room; the bunk room and the kitchen, "where some truly fine meals are created."

"Just like on 'Emergency One'!" my son corroborates.

We are on our way to the garage, or apparatus room, when the beep sounds again. One beep means alert. It would be two beeps for a fire, but the code isn't as simple as that: There are also buzzes and tones.

. . . Cedar Lane. An OB. Rescue Company One ambulance 11:02.

"That's a call for our mobile intensive-care unit," translates Jim. "Medic One is our ambulance that carries EKG equipment on board."

To the kids' delight, a couple of squad members run by us and out the door. Almost before we can grasp their passage, Rescue One, lights ablaze, pulls out through one of the garage's four bay doors.

"Go deliver a baby!" Jim shouts after them.

In 1978 the squad responed to over 9,000 calls. The total will be higher this year. During our visit, only two of the fleet of seven ambulances are in-house. The others are on the road. Jim hustles us into Rescue 14, a $40,000 custom vehicle he describes as a Horton 450 on a Chevy Silverado chassis. We are sitting above 454 cubic inches of four-barrel engine. The car also carries two 20-gallon gasoline tanks. This information drifts past the children, who sit dwarfed in the cab, again awed by a multi-button panel on the dash in front of them.

Jim turns on the four-way flashers, then the beacon rays and the Mars light, then the scene lights. When he hits a set of sirens, the kids cover their ears and squeal.

Back in the hospital compartment we see the first-aid kit, the trauma kit, the drug box and a $1,200 portable suction machine. The kids like the air splints best, and they all want a turn lying on the stretcher.

Squad members spend more or less time, depending on the interest of their group, pointing out the four different kinds of stretchers on the ambulance, the traction splint, the backboards.

"But kids like me to open all the compartments. They can't believe all the storage space we have."

And they like trying on the running gear: "Wow. Is this hat ever heavy!"

Running gear is worn when the heavy-duty rescue trucks go out. Bethesda-Chevy Chase has two of these trucks, each worth upwards of $100,000. The equipment on these vehicles is used for search and rescue, ventilation and illumination, salvage and overhaul. Each carries a 17,500-watt generator and several hugh lamps. We see the Scott air packs with breathing masks and the Cascade tanks used to refill them at the scene of a fire. Endless compartments within the custom-built body of each truck contain jacks, torches, saws, ropes and hand tools. One key piece of machinery is a Hurst hydraulic jaw, capable of exerting five tons of extricating force.

The high point of our visit comes when Jim lifts the kids eight feet up into Resuce 19's cab. It's at least twice the size of the ambulance cab.

"Up here you really feel like king of the road," Jim says.

It's a royal struggle to get the children down, and out to our humble station wagon. They are thrilled by the tools they've seen and the sheer bigness of the truck, but they also comment on the needles and bandages in the patient-care kits, and on the blood stains on Jim's pants. They seem to have sensed the urgency of the men rushing off in Medic One.

It's no surprise, then, when on our way home my son taps me on the shoulder.

"Drive kind of slow, will you, Mom?" WHERE THE SIRENS ARE.

Call in advance to arrange a visit at the Bethesda-Chevy Chase Rescue Headquarters on Old Georgetown Road and Battery Lane in Bethesda (652-0077) or the Wheaton Rescue Station at 11435 Grandview Avenue (between University and Georgia) (949-4044).

You don't have to call ahead to ride the firetruck at the Chevy Chase Fire Station's open house this weekend, kicking off National Fire Prevention Week: Saturday and Sunday, 10 until 4: 8001 Connecticut Avenue, Chevy Chase.