A national poll of 600-plus businesses taken earlier this year established that more than 70% of respondents had experienced toll-call theft at least once in the past five years. By the end of 1993, the poll indicates, 35,000 phone users will have lost $4 billion through phone fraud -- a $114,000-per-target average that the victims, not the vendors, are obliged to absorb. And some phone systems will be breached more than once, a discouraging circumstance attributable in part to small companies' lack of phone-fraud-protection expertise.

But that lack need no longer pertain. The Telephone Accounting and Billing System (TABS) Toll Patrol, a modestly priced hardware/software private-branch-exchange (PBX) plug-in product developed in Israel and marketed here through an American subsidiary, keeps watch over a company's established calling patterns, sending a warning when suspicion-raising divergences are detected.

A toll thief has to be mighty clever to trick the cagey device. The stand-alone unit (no extra PC or call-accounting system is required) tracks every call -- incoming and outgoing -- that passes through a company's PBX. It weighs such clues as the extension reached within the company, the duration of the call, the number that made the call in (if Automatic Number Identification is legal in your state), and the number called out. It sends a warning if, for example, there's an increase in the average duration of long-distance calls, an unusual number of calls emanating from one area code or number, a multiplicity of short-duration incoming calls, or excessive toll charges. The warning continues to be sent (to a specified beeper, PC, or alarm) until receipt is confirmed.

If nothing else, TABS Toll Patrol's eternal vigilance ought to temper employee abuse of company lines. The survey determined that while outside hackers could be blamed for 58% of toll-call fraud, a business's own trusted workers were the suspected culprits for a hefty 11%.

TABS Toll Patrol is from Mer Communication Systems, in New York City (212-594-7871). The base retail price is $1,995.