Chip-equipment company Teradyne ( TER) agreed to sell its connection systems division, a unit that accounted for 23% of its revenue last year, to Amphenol ( APH). The deal is valued at $390 million in cash. The connection systems unit, based in Nashua, N.H., supplies high-speed, high-density connectors, as well as printed circuit boards and backplane interconnect systems. Boston-based Teradyne said the sale "will sharpen our focus on our core test businesses." The company also said "the long-term strategic direction of that business and the rest of Teradyne has been diverging." Shares of Teradyne were down 60 cents, or 3.8%, to $15.33. Amphenol said assuming current economic conditions continue, the purchase should add to its earnings per share in the first year after the acquisition. Amphenol was up 91 cents, or 2.4%, to $39.71.