The SL74HC14 is identical in pinout to the LS/ALS14, LS/ALS04. The device inputs are compatible with standard CMOS outputs; with pullup resistors, they are compatible with LS/ALSTTL outputs.
The SL74HC14 is useful to “square up” slow input rise and fall times. Due to the hysteresis voltage of the Schmitt trigger, the SL74HC14A finds applications in noisy environments.
   
• Outputs Directly Interface to CMOS, NMOS, and TTL
• Operating Voltage Range: 2.0 to 6.0 V
• Low Input Current: 1.0 μA
• High Noise Immunity Characteristic of CMOS Devices