NOTE: THIS STORY HAS BEEN CLARIFIED.

THIRTY YEARS AGO, an accident on I-95 might have brought one 9-1-1 call from someone living near the scene, says Cpl. Joe Cannon.

Today, 9-1-1 might receive 40 cell-phone calls from people driving by.

Half of all 9-1-1 calls now come from cell phones, which are the least helpful for dispatchers.

When a landline is used, the dispatcher's screen shows the name and address of the phone's owner, while another screen displays a map with a telephone icon showing exactly where the call is originating.

That's a huge plus, because 9-1-1 can send help even if the caller is unable to speak.

Calls made from pay phones show the precise location of the phone.

Cell-phone calls display the number, service provider and tower from which the call is being received and an approximate location.

Sgt. Dan Livewell wishes that everyone would use landlines.

"It's better than a cell, especially if you're nervous," he says. If you are using a cell, Livewell pleads, "provide an address."

An important duty of 9-1-1 dispatchers is to assign a priority number to each call, ranking from 0, the highest, to 6, the lowest. It's as much an art as a science. Here are some samples:

0: Assist officer.

1: Crime in progress, or a person with gun.

2: Hospital case or domestic disturbance. Medical calls are instantly transferred to Fire Department rescue.

3: House disturbance.

4: Reckless auto driving, loud music.

5: Disabled auto.

6: Barking dog, small theft or short-dumping.

* Dispatchers who answer 9-1-1 calls have three screens in front of them. When you dial 9-1-1, information about the owner of the phone appears on a screen at the lower left. As dispatchers interview callers, they fill out a form on the lower right-hand screen. That info is electronically forwarded to the dispatch room when completed. A mapping screen above the others locates the origin of the call so that dispatchers can see the surrounding area.

* In all, the city has more than 200 dispatchers and about three dozen supervisors.

* All calls are recorded, as you should know from listening to 9-1-1 calls on TV shows.

* The dispatch room also has Shot Spotter equipment - listening devices installed on private property with the homeowners' permission - that "hears" gunshots and locates them. The program is being shut down because it didn't work well.

* Better technology in the dispatch room is Blood Hound, which helps catch bank-robbers by using an invisible GPS chip embedded in a greenback in a stack of bills. When a teller hands that stack to a robber, an alarm goes off in the radio room and dispatchers see a map showing the suspect's location, direction and speed.

- Stu Bykofsky