Patent ID: 7539889

Claim:
A method at a master device in an infrastructure network having an access point and client devices, each client device having a global clock and a local clock, the respective global clocks being synchronized; the method comprising: reading a master local clock included in the master device to obtain a master local clock counter value; reading a master global clock included in the master device to obtain a master global clock value corresponding to the read master local clock counter value; and sending to at least one slave device data sufficient to determine a relationship between the master local clock frequency and the corresponding master global clock frequency, each slave device being a client device, such that each receiving client device that is a playback unit can use the received data, the local time according to the receiving playback unit's local clock, and the receiving playback unit's global clock value to adjust the slave device's local clock's frequency to synchronize to the master device's local clock's frequency, such that the adjusted local clock provides an adjusted local clock signal that is frequency synchronized to the master device's local clock, wherein the receiving playback unit includes a digital to analog converter that is clocked by a signal derived from the adjusted local clock signal and that is operative to generate analog audio data, and one or more elements operative to provide audio playback.