MIDI In & Out over a single TRS connector

[vandermann]

Hey guys! Any thoughts how to have the MIDI send and receive at a single TRS connector? Maybe something like the old current loop simplex/half duplex!?

Cheers, Vanderson

[Seljer]

According to this: http://www.midi.org/techspecs/electrispec.php only three of the five pins are used so no need to do anything exotic. Just hook it up.

[bluebunny]

I think the OP meant send and receive in one connector?  The MIDI send would be three wires (current loop + GND) and the MIDI receive would be another two (another current loop).  So you'd need a TRRRS?   

[mth5044]

Aren't there 1/8" cables that have five connectors?

[vandermann]

On the Lehle SGoS D Loop the MIDI In/Out are in the same Stereo connector. You can connect two D Loops using just a regular stereo cable, it doesn't need to be crossed over at all. And you can use a regular TRS to DIN 5 cable to have a standard MIDI cable. How they achieve that!?

[slacker]

From a data point of view MIDI is just serial data so to send and receive it you only need 3 lines Transmit, Receive and ground, which you can do with TRS jacks and cables. With only 3 wires you can't make it properly isolated though, as both ends would need to share the ground.

I had a look at the manual for the  Lehle SGoS and it's not very clear but it seems to say, depending on what mode it's in, it can either send or receive external MIDI message, I can't see anything about it being able to do both at once so the DIN to TRS adaptor only needs to be one way. When it is linked to other units using a TRS cable and put in the correct mode the units could change how the interface works to enable two way communication that only works between the units.

http://lehle.com/EN/Lehle-D.Loop-SGoS/MANUAL#go

[vandermann]

From a data point of view MIDI is just serial data so to send and receive it you only need 3 lines Transmit, Receive and ground, which you can do with TRS jacks and cables. With only 3 wires you can't make it properly isolated though, as both ends would need to share the ground.

I had a look at the manual for the  Lehle SGoS and it's not very clear but it seems to say, depending on what mode it's in, it can either send or receive external MIDI message, I can't see anything about it being able to do both at once so the DIN to TRS adaptor only needs to be one way. When it is linked to other units using a TRS cable and put in the correct mode the units could change how the interface works to enable two way communication that only works between the units.

http://lehle.com/EN/Lehle-D.Loop-SGoS/MANUAL#go

Regard to the D.Loop manual all SGoS in the network are configured on mode 3 (programming mode). they can receive and transmite at same time. Please take a look on the video below. Cheers.

[slacker]

You could do it like this, I don't know if this is what they do it.
In the manual it says to link two of them you have to set one to transmit program change commands 11, 12 and 13 and the other one to transmit program change commands 14, 15 and 16. The one you set to transmit 11, 12 and 13 could set its tip to be transmit and its ring to be receive. The one set to transmit 14, 15 and 16 could do the opposite so when you connect them with a TRS cable send on one is connected to receive on the other. This would be pretty easy to do, for example you could use a DPDT relay to switch the tip and sleeve depending on which option was selected.
I'm not sure how you would do it to connect 3 of them because I can't see how they do that, the ones I looked at only had one MIDI jack.

You could do something similar for making it send or receive when connected to an external device using the DIN to TRS cable but it couldn't do both at once unless the device at the other end supported it as well.

[vandermann]

I thought something like that! What you guys think!?

[slacker]

That very clever, looks like it should work to me. You'll get collisions if they are both transmitting at once but you can prevent that happening in your software.