 This study is a preliminary study designed to determine the safety and effectiveness of HFCWO using the InCourage vest system as an airway clearance technique for the treatment of CF. The study will compare HFCWO to the most commonly used airway clearance technique in Canada, namely the Positive Expiratory Pressure technique in patients with CF over a period of one year. As this is a preliminary study, it will not be able to determine if the vest is equivelant to PEP, but will provide the information needed to plan a larger study to answer that question. 