The jeep's primary command and reconnaissance roles of course necessitated fitting many kinds of tactical communication equipment. The first standard production fitting was for the SCR-193 radio, placed on either side in the rear of a jeep, on top of the rear wheel well. For proper reception, this included radio interference suppression shielding, so indicated by a suffix 'S' on the jeep's hood registration number. In 1943/1944, the Army shifted to FM radios, and new fittings were developed for those. At least fourteen Signal Corps Radio set fittings were standardized, including for the SCR-187, SCR-284, SCR-499, SCR-506, SCR-508, SCR-510, SCR-522, SCR-528, SCR-542, SCR-608, SCR-610, SCR-619, SCR-628, SCR-694, SCR-808, SCR-828, and VRC-l.