Abstract: We describe a method of synchronizing a teleconference comprising audio carried on a telephone network and a digital data stream carried on a computer network. Audio at a first node is characterized to determine audio characterizing data. A digital data stream for the teleconference is also input at the first node and the audio characterizing data is inserted into the digital data stream and forwarded over the network. The audio and digital data streams are received separately at a second node of the system, and the audio characterizing data is extracted from the digital data stream and processed in conjunction with the received audio to determine a first-second node time offset. The audio and digital data streams are then synchronizing by adjusting, for example, a relative time delay of the received audio and digital streams at the second node responsive to the determined time offset.