Hm, I'm not making a lot of sense of this.

The connector you refer to as 'Type A' would seem to be a 3.5mm stereo Jack male connected to a midi DIN female socket. I see that such things are available via the internet, so I assume that the 3.5mm jack is wired correctly for midi use. The connector at the other end of the standard midi cable (you say) you refer to as 'Type B' and this would appear to be another midi female DIN socket, connected to ? What is this plug, and what is it connected to (i.e. socket) on the 'BlackBox'?

You show one side of the 'Prodipe', are these supposed to be midi sockets? They look like they might be, but they seem to be rather recessed. Is this just because of lighting? if they are recessed, then DIN plugs might or might not connect properly?

You show a midi (I assume) cable going to an IN socket on the Prodipe, but your pics do not show when this cable is coming from. It should be coming from an OUT connector on another midi device?

Some clarifications would be a help.

Geiff

You may just need an A-B converter on the output of the Plantwave, may save a bunch of trouble.

Google search MIDI TRS A/B Converter for something similar to
https://polarnoise.com/product/midi-a-to-b-adapter-3-5mm-trs-cable/

Then your output should match the B output of your other devices.

If I am seeing things correctly, with your current setup the A signal is going to the splitter, which it may not like.

Thanks for your help. I didnt get a notification by email of your replies so only just realised there were responses ! Since then i got hold of a Type A to Type B 3.,5 TRS cable from Scapesound (thanks for the link Jason!) - The diagram below shows the setup now. When i plug the standard MIDI cable directly into my Behringer K2 synth there are midi signals. However the Prodipe midi splitter still shows no midi response which is a problem as i need to control a number of synths at once with the plantwave ! Geiff thank you for your questions. I have also included below detailed pics of the Prodipe from all angles ! I should add that normally i have no issues with the Prodipe from any other device including my arturia keystep. The diagram above shows that the midi cable marked with an X goes into the IN1 of the Prodipe from the previous diagram (see the cable marked X) the output would be the red midi cable on the prodipe OUT1 to a synth for example. When a midi signal is present the LED lights flash normally. Hope this clarifies things more. Thanks again everybody !

Thanks for the extra information.

I have to assume that all the cables are OK, and therefore have the potential to work correctly.

When looking at situations like this, I'd always suggest that you start with the simplest setup, i.e. device A connected to device B, and make sure that is working correctly, and then add further devices one-by-one, making sure that each change continues to work.

Always note that where devices are connected, you connect the OUT of one device to the IN of the other. The device needs to be ON, even if it's not doing anything.

Are there any channel settings involved here? Some midi devices may send on a specific channel, or receive on a specific channel, and if the channels are different then a signal may be going through, but it's not being listened to.

Geoff