The PAC RP4-CH21 RadioPRO4 Interface is an all-in-one solution designed to simplify aftermarket radio installation in select 2013-2018 Dodge, Jeep, and Ram vehicles equipped with MS-CAN databus radios. This innovative interface comes pre-loaded with essential software for amplifier retention and steering wheel control, along with navigation-based output signals. It allows for the replacement of the factory radio while retaining crucial factory features.

Key retained features include steering wheel audio controls, the factory amplifier (though fader control may be lost with Chrysler-built amplifiers), the Driver Information Center (DIC) with vehicle settings, and the factory back-up camera. The RP4-CH21 also preserves HVAC climate controls, blind spot detection, and lane departure warning systems. Additionally, it provides data bus driven outputs such as retained accessory power (RAP), vehicle speed sensor (VSS), illumination, reverse trigger, and parking brake, which are vital for installing navigation receivers. The interface supports assigning a secondary function to each steering wheel control button, offering enhanced customization.