application_number US 2350901 A description the following description of the presently contemplated best mode of practicing the invention is not to be taken in a limiting sense but is made merely for the purpose of describing the general principles of the invention the scope of the invention should be determined with reference to the claims referring to fig1 an exemplary turbo code encoder is shown wherein one embodiment of a turbo code trellis termination design terminates one encoder 10 a first encoder while disabling another encoder 10 u2032 a second encoder and at a different time terminates the other encoder 10 u2032 second encoder while disabling the encoder 10 first encoder the encoders first and second encoders 10 10 u2032 of the turbo code encoder of fig1 are constituent encoders configured in a parallel concatenation it is well known in the art that a constituent encoder employ a configuration of modular adders 17 20 26 28 30 24 and 25 and shift registers 18 21 22 coupled through nodes such as node 32 to produce output bits including tail output bits x t y 0 t y 1 t for example depending upon the encoding scheme fig1 is just one example of such a parallel concatenation of constituent encoders wherein an interleaver device interleaver 16 is employed between an input for x t and the second.