A system for producing fluids from a subterranean zone comprises a tubing string disposed in a well bore, the tubing string adapted to communicate fluids from the subterranean zone to a ground surface. Upon reception of the connection setup message at a destination terminal device, a confirmation message is returned to the source terminal device on the identified route, whereby a switching information for a following message transmission is stored in the network nodes that have been traversed. In an implementation of the vacuum toilet as a vacuum urinal, the system may provide either water flushing or waterless flushing. The optical amplifier may include both a gain equalizer and automatic level control circuitry to respectively maintain substantially uniform gain at wavelengths within an optical signal band and maintain constant output power.