By ERIN ARVEDLUND

Dow Jones News Service

NEW YORK (Dow Jones News) -- Turmoil in America's heartland has brought to light some of the high-tech tools used in the dark business of counter-terrorism.

Authorities are on the trail of a cryptic fax said to describe the Oklahoma federal building devastated in last week's bombing, while President Clinton has called for a series of broad steps to give the government new powers to fight terrorism.

As a result, companies such as Comverse Technology Inc. and Avert Inc. may see their technology -- and their stock -- in more demand.

Comverse's AudioDisk, used by police and intelligence agencies to record and store wiretap data, now accounts for half of the company's business. Old methods of wiretapping relied mostly on reel-to-reel tape recorders, while Comverse's product uses technology similar to that of compact disks to record digital signals.

Designed primarily for law enforcement and intelligence gathering, the AudioDisk can monitor hundreds of telephone and fax-machine lines simultaneously and retrieve data instantly.

On Monday, Comverse stock rose 68 3/4 cents, or nearly 5 percent, to $14.93 3/4 a share Monday afternoon on the Nasdaq Stock Market.

``This is one of the first times (our stock) has reacted'' in tandem with an event like the bombing in Oklahoma, a spokesman for Woodbury, N.Y.-based Comverse said.

Separately, President Clinton's proposal to give the FBI increased authority to comb through hotel registers and to search phone logs, as well as greater access to credit-card records, might also have lifted shares of Avert.

Avert, based in Fort Collins, Colo., performs background information services for employers. The company's stock jumped $1.62 1/2, or 22 percent, to $8.87 1/2 a share Monday afternoon on Nasdaq.

AP-WS-04-24-95 1555EDT

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