A method for data communications includes receiving a time-division-multiplexed (TDM) input signal carrying a payload comprising data and determining whether the data comprise synchronous or non-synchronous data. A first encapsulation scheme is selected if the data comprise synchronous data, and a second encapsulation scheme is selected if the data comprise non-synchronous data. The data are encapsulated for transmission over a packet-switched network in accordance with the selected encapsulation scheme.