Cascading 2x MIDImerger, can I simplify the schematic?

Design Concepts
1

I’d like to cascade 2x MIDImerger so I effectively have a 3 -> 1 merge. I saw via this post that someone has already done this, and it was successful:

http://discourse.midibox.org/t/topic/14743

In that post, they mention that both mergers share the same power supply. Is it possible to simplify it further? For example, if I’m using 2x PIC16F88 and have PIC #1 -> PIC #2:

  • Can I omit the 6N138 on the cascaded input between the two PICs and connect TX from PIC #1 directly to RX of PIC #2?
  • I should only need one Power LED and only the second Tx LED. Can I just leave pins RB0 / RA1 of PIC #1 disconnected?

This is the schematic I’m looking at http://www.ucapps.de/midimerger/midimerger_pic16f88.pdf from this page http://www.ucapps.de/index.html?page=midimerger.html

Thanks!

2

Actually I just found this part of the documentation, which appears to answer both of my questions. In case anyone else doesn’t see this on the http://www.ucapps.de/index.html?page=midimerger.html MIDImerger page, I’m quoting it here for discoverability:

Quote

All LEDs (and the corresponding 220 Ohm resistors) are optional.

The 78(L)05 based PSU circuit is not required, if the merger should be used in an environment where a stable +5V supply is already available.

The optocoupler circuit(s) can be left out, if the MIDI Out signal is already available at TTL level, and supplied from the same power source (or at least, if the circuits are sharing the same ground connection).