1. A telephone voice changer for connection between a hand set and a telephone set comprising: a first port means for connection to a hand set, a second port means for connection to a telephone set, and voice changing means for selectively changing the frequency content of voice signals transmitted between said first and second ports, and including an analog to digital converter means whose input is connected to said first port means; a digital to analog converter means whose output is connected to said second port means; a digital processor means having an input and an output for receiving, storing and sending signal from its input and to its output; a serial to parallel converter means connecting said analog to digital converter means to said digital processor means input; and a parallel to serial converter means connecting said digital processor means output to said digital to analog converter means.