A laboratory liquid handling system includes a pipetting module, a lab member, and a drive system. In case of an upward movement of the elevator cabin, hydraulic oil is conveyed by a pump driven by an electromotor from the tank through the control valve unit to the lifting cylinder. A background sound receiving side demultiplexes, in a demultiplexer, received multiplexed data into received encoded speech data and encoded background sound data which are decoded in the receiving section and the background sound reproducing section respectively, and in the receiving section, a sound in which received speech and background sound are superposed is outputted from a receiver. The method further includes processing multicast packets from the source according to the multicast routing table.