Abstract: A jack assembly is provided with a contact switching system for receiving a coaxial plug. The assembly includes an insulative housing having a terminal-receiving chamber and an aperture communicating with the chamber for insertion therethrough of the coaxial plug. The housing includes a terminal pivot support in the chamber. A fixed terminal is mounted on the housing and includes a fixed contact portion located in the chamber. A movable terminal is mounted on the housing and includes a cantilevered spring contact arm projecting from the terminal pivot support for pivoting thereabout. The cantilevered spring contact arm includes a first contact portion for contacting the contact portion of the fixed terminal and a second contact portion for contacting the coaxial plug when inserted into the chamber. The spring contact arm is resiliently preloaded to bias the first contact portion against the contact portion of the fixed terminal.