A method is provided for Voice over Internet Protocol (VoIP) devices to communicate over an Internet Protocol (IP) network. The method includes synchronizing the VoIP devices using one or more dual-tone multi-frequency (DTMF) codes over a telephone network, retransmissions of voice packets in bursts, retransmissions of voice packets following a time lag, adjusting the number of retransmissions based on quality of service, retransmission of a missing voice packet identified in a list received from a peer device, discarding low energy voice frames in a jitter buffer to prevent overflow, stopping playout at a low energy voice frame when the jitter buffer is below a minimum buffer size, and selective transmission and retransmission of voice packets based on their energy levels.