Abstract: A telephony system includes a packet-based data network that is coupled to various network elements. The network elements include interface devices that are coupled to corresponding stimulus devices. The stimulus devices may include stimulus telephones or a telephone exchange system. Each interface device receives a stimulus message from a corresponding stimulus device. The stimulus message is encapsulated by the interface device into a packet, such as an Internet Protocol (IP) packet. The packet is communicated across the data network to the target device, which may be another interface device. At the receiving end, the interface device receives the packet, decapsulates the packet to retrieve the stimulus message, and sends the stimulus message to a corresponding stimulus device.

Abstract: A packet network interface for delivering streaming data to an analog output is described which can compensate for a sampling rate mismatch between the far-end transmitter and the local receiver by monitoring the rate of reception of packets and adjusting the local (receive) sampling rate responsive to said rate of reception. Typically, the rate of reception of packets is monitored by monitoring the level of a jitter buffer used to compensate for variable delays in the rate of reception. If the average level is too high or two low, this is a likely indication that there is a rate mismatch between the far end and local sampling rate. Adjustments are then made to the local sampling rate to adjust for such a mismatch.