(FORTUNE Magazine) – These days "customer service" usually means wrestling with an automated system indefinitely. But if one company has its way, all that shouting might actually yield more than a headache. Nice Systems, an Israeli software company, recently launched new technology that can tell which customers are truly steamed--and steer them toward help.

In plain English, if you go from trying to rationally explain to a rep that you don't get cell coverage in your bathroom, to screaming at the top of your voice that you're defecting to their No. 1 competitor, the system flags you and alerts a higher-up.

To measure emotion, the program registers things like pitch and tone at the start of a call, and any major fluctuations can raise the alarm. It also scans calls for a lexicon of words--selected by each company--that should cause concern, such as "cancel," the names of competitors, and any, ahem, phrases including obscenities related to the rep's mother.

Nice already has 15 clients using the system, including a unit of FedEx. So next time you're stuck in automated-call-center hell, remember: Sometimes it pays to be a pain in the neck. -- Nadira A. Hira