Abstract: A data processing system for receiving sampled analog data and automatica converting, processing, compacting, expanding and storing the data in digital format and also displaying the data in alphanumeric format. The analog data signal may be from a temperature probe, for example, that is launched from a ship and transmits sampled temperature data as it free-falls in the ocean. The system has the capability of providing all of the general information, data and control signals, all in proper digital format, for permanent storage or for operating a teletype machine in total run real time to provide a real time output chart. The system includes compaction and expansion capabilities so that data that is being sampled at a rate that is faster than the readout rate of the teletype machine may be internally compacted and then expanded into the teletype machine when the data sampling rate is slower than the readout rate of the teletype machine.