Motorola Inc., the largest U.S. mobile-phone maker, acquired RadioFrame Networks Inc.'s digital-phone technology business to gain its lower-cost, power-efficient capabilities.

Terms of the transaction weren't disclosed. The iDEN, or Integrated Digital Enhanced Network, business will be integrated into Motorola's home and networks mobility unit, the company said today in a statement. The unit accounted for about a third of sales last quarter.

RadioFrame will join BitBand Technologies Ltd., a maker of video content delivered over the Internet, in the home and networks business. RadioFrame, based in Redmond, Washington, owns base stations and amplifiers that can enhance push-to-talk capabilities on mobile devices, Motorola said.

Motorola, based in Schaumburg, fell 20 cents to $8.28 at 4 p.m. in New York Stock Exchange composite trading. The shares have climbed 87 percent this year.