programmed with one or more control algorithms configured to control the cabin air stream temperature and flow rate an input air stream 150 may be supplied to the compressor 102 where it may be compressed and output as a compressed air stream 152 the input air stream 150 may come from a ram air duct the input air stream 150 will be at a temperature and pressure the pressure sensor 122 may sense the pressure of the input air stream 150 and may communicate to the controller 132 a signal indicative of the pressure of the input air stream 150 by way of communication line 156 the compressor 102 inlet temperature may be determined from the compressor inlet pressure sensed by pressure sensor 122 and airplane data typically available to the controller 132 alternatively the compressor 102 inlet temperature may be measured directly by way of optional temperature sensor 114 which may communicate to the controller 132 a signal indicative of the temperature of the input air stream 150 by way of communication line 154 the temperature and pressure of the input air stream 150 depend on the source of the input air stream 150 and or the ambient conditions for example when the aircraft is on a tarmac in a warm climate the temperature and pressure of the input air stream 150 may be relatively higher than when the aircraft is moving at altitude.