Communication systems and methods are described that enable mobile devices to route telephone calls via an enterprise telephone system. The communication system is configured to receive via a data channel a request from the mobile device. The mobile device corresponds to a user making a call. The server receiving the request includes a private branch exchange (PBX) and one or more other servers hosted by or coupled to the enterprise. A first call leg is initiated over a first voice channel in response to the request. The first call leg is coupled to the server and mobile device. A second call leg is initiated over a second voice channel, and the second call leg is coupled to the server and a client device corresponding to an intended call recipient. A voice conference call is formed between the mobile device and client device by joining the first and second call legs.