Continental Flights Came Within 600 Feet On Wednesday

There was another near mid-air collision at Newark Liberty Airport Wednesday, forcing the FAA to call an emergency meeting on the matter.
WCBS TV News.

“They refuse to spend a few dollars to get up-to-date equipment in the hands of traffic controllers and airports here in New York,” Sen. Schumer said.

What kind of equipment can be purchased that would keep a controller from giving out the wrong frequency?