Abstract: Logic devices for frequency encoded trinary logic signals are simulated by standard binary circuits. The binary circuits include frequency sensing and frequency selecting devices at the inputs and outputs thereof for decoding the frequency encoded trinary logic signals to binary level logic signals and for frequency encoding the resulting binary output to trinary logic signals. Optical encoding using the three primary light frequencies provides a convenient trinary signal format for the frequency encoded signals. A latch register, a shift register, a half adder and full series and parallel adder circuits are disclosed.