The 3.5 mm connector is a heavy-duty coaxial connector that can operate at up to 34 GHz without mode switching. The air dielectric filled interface of this pin and socket type connector features a 3.5 mm outside conductor diameter. This connector interface works with SMA and 2.92mm connectors and can withstand several mating cycles without causing harm. Hewlett Packard invented the 3.5 mm connector in the mid-1970s, and Amphenol later marketed it as APC3.5.