PrimeCo Personal Communications, L.P. (later known as Chicago 20 MHz, LLC) was a joint venture of Bell Atlantic, Nynex, US West and AirTouch Communications, and was the first wireless telecommunications provider to turn up CDMA service on the PCS (1900-MHz) band in late 1995. When the company was founded, it had its headquarters in Westlake, Texas. At a later point its headquarters were in Itasca, Illinois.

Hailed as the largest wireless phone service launch in U.S. history, the company successfully launched in 19 major U.S. cities. The company's original cell site equipment suppliers were Motorola and AT&T (now Lucent Technologies), and the original telephone supplier was Qualcomm Personal Electronics, a joint venture between Qualcomm and Sony Electronics. The company served parts of the Midwestern and Southern United States. The two primary service areas included Wisconsin, northern and central Illinois, and northern Indiana; and parts of Virginia and North Carolina, as well as the Gulf Coast from Key West, Florida to Houston, Texas. PrimeCo had the license to operate in Hawaii.