Abstract: An engine trim tachometer capable of use with a variety of aircraft engines. More particularly, the present tachometer unit is characterized by a plurality of separately operating engine speed parameter measuring channels, an engine variety selection switch individually associated with each channel and interlockingly arranged for common movement whereby each channel remains associated with one engine variety, a plurality of operator selective interface connectors for establishing the necessary electronics required by each individual engine variety, and a clock driven programmable divider for establishing the division ratio for each channel associated display meter.