They are highly trained and only a phone call away, and all it takes is a 911 call to get local emergency responders into high gear.

Whether it is crime, a fire, a car accident or medical emergency, 911 dispatchers are trained to make sure the right emergency responders head to the scene.

While police, fire and EMS each have their own dispatchers, it all starts with the 911 communications centre at Waterloo Region police headquarters.

Every 911 call made in Waterloo Region goes to one place, where five people are ready to pick up the phone and take action.

When CTV News visited, between midnight and 9:30 a.m. there were 70 emergency calls and 97 non-emergency calls. It was considered a slow day.

Lisa Muhlbock works at the 911 Call Centre, and she says the number of calls can vary widely.

"You start out here, it goes up here, it goes down here and that could be a span over an hour or that could be a span over 15 minutes."

Muhlbock faced a steep learning curve when she was looking for a career change four years ago, but her college education and training taught her how to recognize the needs of each caller.

But it's more than that, Muhlbock says, it's also about knowing "how the services work and how they interact with each other, which is something I didn't know."

That includes understanding when a situation meets the criteria for all three emergency services to be dispatched.

Waterloo Regional Police Insp. Greg Lamport says "Those calls are considered tiered response calls where we will send police, fire and EMS to offer assistance to the people who are calling in."

A situation like a car crash can meet those criteria, starting with traffic service officers.

Sgt. Fred Gregory is with the Waterloo Region police traffic branch, where he has worked for about half of his 34-year policing career.

He says "At every collision scene I've been at, or medical call, everyone knows their roles and we just sort of, it's like a well-oiled machine. It just takes care of itself."

And that's a good thing, since the Waterloo Regional Police Service responded to 277,000 calls for service in 2010, with nearly 11,000 of those being collisions.

But while the calls are never easy, Gregory says having that responsibility can be gratifying.

"Collision investigation is not a simple task, with it comes a lot of responsibility…Not only are you on the front line, but these types of calls you're always there to help people."

The mobility of police cruisers means they are often on scene first, but firefighters are usually right behind them, and not just for fires.

Coming up in part two: Why firefighters are responding to more than just fires.