optocoupler alternatives

[otivlasc]

I wanted to ask some advice as I'm having difficulty getting this up and running:

I've used a TLP785 instead of the SFH618 for the optocoupler, so my first thought is that that is the issue - I'm having a hard time understanding if the TLP785 is too slow for this application.

Here are the switching characteristics from the datasheet:

What do you think? It's a bit difficult to find this SFH618 where I am, do you know any alternatives that could definitely work?

Thanks so much!

[ravique]

I used 6N138 for similar project (midi chorder, that recieves one midi note and sends three to the output). Overall latency was adequate.
I will try to implement this project on 6N138 too. I will try to measure the latency.