Delta Modulations Training System that consists of several computer education programs is described. Two of these programs are presented in the paper. The DMTS system illustrates the operation of the delta modulators not only with step size adaptation, but also with sampling interval adaptation. Thanks to the possibilities of simulators the measurements of the dynamic range DR, SNRmax ratio and average bit rate (BRavg) can be made. The suggested simulators are very useful for monitoring and measurement the channel errors influence on the received voice quality.