The Decommutator section of the ApolloPCM is designed to support all of the IRIG class Features including variable word lengths per Channel and non-standard PCM frame formats. The Input serial bit stream to the decommutator is either TTL or RS-422 differential levels with input data rate capability from 10 bits/sec(bps) to 20 Mbps. Two on board 12 bit DACs are standard features that give the ApolloPCM standalone word selection analog capability. The word by word parallel output of the ApolloPCM is available to the user in sevarel different forms,through a high speed memory buffering circuit for direct storage to the host computer for post decommutator analysis. through a over-the -top connector to multiple vendor DAC cards, And through many different windows GUI displays including oscilloscope/strip chart,FFT spectraul, numeric,bar graph and dials. there is also a full PCM simulator on board that has all the same frame and word features as the decommutator with user definable wavw forms are fixed data values on a word per word basis.