System and methods for providing telecommunication functions on a mobile device are disclosed. An inbound call request is received, a call control interface is presented for a user to choose among a plurality of communication modes by which an inbound call is to be established. Call control data selecting a mode of communication is received through the call control interface. Communication is established according to the selected mode of communication. An outbound call request identifying a callee device is send from a mobile device through a packet network to a telecommunication service provider, and a call connection from the mobile device to the telecommunication service provider is established through the telecom network. The telecommunication service provider places a call to the callee device and combines the call connection from the mobile device to the connection to the callee device to establish a single joint call connection.