More fundamentally, and as you (SteveS) obviously appreciate, the cable expects to plug into a 'USB host'.

USB is fundamentally a hierarchy based system, every connection must involves a host a one end and a client device at the other.

A hub or splitter is a host that does nothing other than allow multpile clients to connect to it on one side, passing all those connections on to the host it is in turn plugged into.

Inspired by this topic I've ordered a MIDI in/out to USB (host) cable as I think that I can almost certainly use that to get my PC to see MIDI signals from a USB keyboard that is plugged into my MOD DuoX (or maybe even see signals from more than one controller?) .

The MOD DuoX acts as USB host, but also has MIDI in & out. I believe that as well as using the keyboard directly on the MOD DuoX I can also pass the MIDI in from it to the MIDI out connections & thus on to the PC (i.e. have the MOD DuoX provide MIDI thru)?

I base that on the 'MIDI USB' section of this page: https://wiki.moddevices.com/wiki/MOD_Web_GUI_User_Guide#Expanding_Controls

See especially the first & second pedal board images in that section. It should be possible to run a virtual patch cable between the MIDI in & out connections that are pointed to by the red labels (while also having other virtual patch cables going from MIDI in to MIDI devices on the pedalboard).

I think I'll also be abe to see MIDI in from the PC?

Somthing like that, with the added (I don't think it's there already?) facility to 'talk' over IP to another copy running on a different computer & share MIDI connections would be a particulaly fascinating possibility!

Following David's research, I discovered that Apple has built in support for virtual MIDI networks in both MacOS and IOS. And there are drivers for Windows. These use a protocol called RTP-MIDI and no extra hardware is required. It should allow you to share MIDI across your local Ethernet / WIFI network and between applications and machines without any extra USB hardware.

https://www.tobias-erichsen.de/software/rtpmidi.html
https://support.apple.com/guide/audio-m ... ms1012/mac

I also found a hardware approach:
https://www.iconnectivity.com/mioxm

I see references to Reaper, Ableton, Logic, and Bitwig when searching.
I haven't yet tried this.

Thanks, Tony. That Mio solution does look like it would work - but for $300 I'd rather just get a second keyboard! (I'm regretting the 25-key I have as there was a 37-key model that was only about an inch wider!! )

Many years ago I used rptMIDI (I'd forgotten about it) but IIRC, I was still using cables. Anyway, I downloaded again and re-installed it, and set it up (it "saw" my iPad) but I can't find anything anywhere that tells what to do to configure this on the iPad side. The only things I'm seeing (like the link you provided) is how to do the "Audio MIDI Setup" for Macs.

It appears that there is no MIDI configuration at the IOS level, only whatever application you are using (like Garageband, for example).

Try these instructions and let us know if you're successful:
https://www.lifewire.com/use-ipad-for-w ... er-1994720

I also found the below regarding Aggregate Devices and MacOS and DAW/software, but this doesn't establish a network connection to an IOS device.

https://support.apple.com/en-us/HT202000

Yup. Found that. Yeah, it looks like that iOS side configuration has to be done via a specific app.

I have yet to try that software solution that David pointed to...

HAH!!

As is usually the case, not thinking through the use-case, and as a result not asking the right question, it's really hard to get to a solution!!

I have solved this problem!!

So what I was asking (and what I was thinking) was about connecting a single USB device to more than one USB host.

"connecting"

I didn't specify (and hadn't really stopped to think about) whether both connections had to be active. In this case, of course, it wasn't a requirement. What I wanted to be able to do was to provide MIDI input to apps running on either of two hosts without having to screw around with cabling, but didn't need to connect to both simultaneously. Thus what I needed was not some way of splitting the signal, but of switching the signal.

So what I was actually in need of was a USB switch.

Turns out there are literally dozens of these out there, and relatively speaking, dirt cheap. Considering the host-side as the "in" and the device-side as the "out", there are two-in and one-out, two-in and two-out, two-in and four-out, some powered and some un-powered, some just have a switch button, some have a wired button so the switch can be tucked away with just the button on the desk/wall, I even found one that has a IR remote!! They range from around $10 to as much as $40 depending on features.

I bought this one:


The cable at the top is coming from my Casio piano, the two cables at the bottom L & R go to my iPad/laptop respectively, and the center bottom cable is going to a 5v USB power supply.

And it works like a charm. I can have both my Nektar 25-key controller and my Casio full-88-weighted-key piano/keyboard plugged into this thing, and push a button to toggle them going into either my iPad or my laptop.

Ta-daaaah!!

Ah. Classic!

Glad to hear it.


Fascinating. Somehow I'd not come across those either. An idea solution for my use current case too! Thank you.