[techhelpbb]

Your schematic is unavailable, and I'm still swamped I'm very sorry about this.

It sounds like you have the right idea, however, please be aware that the source and sink of the other families of TTL are different.

I'd advise people to stick with the 74HC14 on the input side. Though the straight 7414 will work fine in this circuit, the BJT output stage can have some other issues in the capacitive realm.

In the original design we picked a pull up for the NPN transistor in the optocoupler that could accommodate the higher input requirements of the the 7400 series chips because I had considered tri-state and open collector outputs. It's not so easy to get 74HC16 or 74HC17 open drain parts.

For this application you don't need open collector, open drain or tri-state outputs from this circuit. The 74HC04 is quite efficient for the power it uses...just be sure to tie any inputs you do not use to one of the power supply rails...otherwise if you merely get near it, it might actually change state because of the 74HC series high input impedance. Now, you'd think that if the other gates in your integrated circuit were not actually driving any other circuits it wouldn't matter...but the noise from them jumping all around can walk back into the circuit's power supply locally.

I'm going to put my foot down and promise I'll have the documentation mostly done by Wednesday morning at the latest. It's entirely my issue delaying this as I have problems with my eyes.