A summary of Southern California-related business litigation developments during the past week.

Alarm Firm Alleges Unfair Trade: Magnum Auto Security Systems sued three competitors and a manufacturer, alleging that they copied its alarm systems, provided it with inferior parts and tried to drive it out of business. The Superior Court suit contended that Precision Electronic Engineering of Van Nuys stole designs to Magnum alarm systems while manufacturing them in 1987 and 1988 and marketed them to David Levy Co. of North Hollywood, Delta Vehicle Security of Glendale and B&B; of Van Nuys. The suit said the companies fixed prices below cost to try to bankrupt Magnum. Precision also shipped defective products to Magnum and cut off supplies when Magnum refused to agree to pay more for the parts, the suit said. (Filed Aug. 20, 1990. Case No. BC008558.)