Award winning Mobile Office Phone System OnRelay?s Mobile Cloud Exchange (MCX) is a smartphone based corporate phone system. MCX is a SaaS, cloud-based, software-only solution for mid size customers. It eliminates desk phones and their expensive on-premises VoIP networking infrastructure, and does not require any up front investments. Unlike offerings such as Virtual / IP PBXs OnRelay is 100% cellular and smartphone based. MCX is patented, it works over any cellular network and does not rely on VoWiFi or VoIP over cellular data.