HTL (High voltage-Transistor Logic)

The signal levels are typically V_low ≤ 3 V and V_high ≥ V_B - 3.5 V. The signals are transferred symmetrically and evaluated differentially. Because of this and due to the high voltage level, HTL encoders have excellent EMC performance.

Inverted HTL signals must not usually be connected directly to the inverter's encoder input, as the input stages may be overloaded and thereby destroyed in certain circumstances.