MIDI Spec A/B/DIN question

[oldgearguy]

I'm relatively new to the TRS convention for MIDI connections, so I started poking around the net reading specifications, etc.

One question I have - the TRS spec seems to limit the length of a cable to 2 meters (approx. 6 feet).  The original MIDI spec for DIN connections is 50 feet.
Can you in fact use TRS MIDI for distances longer than 6 feet?  Does it depend on the transmitting and/or receiving device?  Does it differ if you use a TRS to DIN adapter and connect the device to a traditional DIN MIDI socket?

Also - given that a number of MRCC slots have all 3 MIDI types, can the MRCC support parallel connections (i.e. - using both MIDI A and DIN for a slot?)
understanding of course that the information sent will be identical.

thanks

[Jesse Johannesen]

I'm relatively new to the TRS convention for MIDI connections, so I started poking around the net reading specifications, etc.

One question I have - the TRS spec seems to limit the length of a cable to 2 meters (approx. 6 feet).  The original MIDI spec for DIN connections is 50 feet.
Can you in fact use TRS MIDI for distances longer than 6 feet?  Does it depend on the transmitting and/or receiving device?  Does it differ if you use a TRS to DIN adapter and connect the device to a traditional DIN MIDI socket?

Also - given that a number of MRCC slots have all 3 MIDI types, can the MRCC support parallel connections (i.e. - using both MIDI A and DIN for a slot?)
understanding of course that the information sent will be identical.

thanks

I can't say I've researched the range issue yet, but I can look into it. From what I understand however I believe you would be able to use both out ports at once, I'll report back once I get confirmation.
Jesse

[Flounderguts]

I use MIDI TRS over long cable runs...I actually use it with a patch bay, and my longest cable is 50 feet. It works fine, but there is a bit of latency.

[0xF0]

I use MIDI TRS over long cable runs...I actually use it with a patch bay, and my longest cable is 50 feet. It works fine, but there is a bit of latency.

You do realize that the length of a cable has infinitesimal effect on latency, right? The speed of propagation in wire is about 300,000,000 meters per second, so your 50 feet of cable add about 50 _nano_seconds of latency.

[Darryl]

I'm relatively new to the TRS convention for MIDI connections, so I started poking around the net reading specifications, etc.

One question I have - the TRS spec seems to limit the length of a cable to 2 meters (approx. 6 feet).  The original MIDI spec for DIN connections is 50 feet.
Can you in fact use TRS MIDI for distances longer than 6 feet?  Does it depend on the transmitting and/or receiving device?  Does it differ if you use a TRS to DIN adapter and connect the device to a traditional DIN MIDI socket?

Also - given that a number of MRCC slots have all 3 MIDI types, can the MRCC support parallel connections (i.e. - using both MIDI A and DIN for a slot?)
understanding of course that the information sent will be identical.

thanks

That is correct, the MIDI.ORG spec says 2 meters max for TRS adapter cables and they should be shielded twisted pair. Maybe because 3.5MM jack cables are who-knows-what wiring they don't trust them? Dollar store cables might be 3 strands of super thin wire for all we know. I'm speculating, but I think if the cable was made with "MIDI" grade shielded twisted pair it would probably go much further. So far we haven't noticed any problems using dollar store 6 foot cables but we haven't tried longer. 

For MRCC inputs, you can pick 1 of the input connectors. For instance, for Input 1, you can pick A, B or DIN. The 3.5MM jacks are switched, so when a TRS jack is plugged in it disconnects the other jacks. There is only one optocoupler per input.
For MRCC outputs, you can use the shared port connectors simultaneously. They are essentially wired like thru ports. 

By the way, on the Remote 7, the connections from the RJ45 to the Remote are MIDI, and those signals are not electrically repeated. So in theory you should subtract the length of the Ethernet cable from the max length coming out of the Remote. That is, I would not suggest using a 50' Ethernet cable, and 50' MIDI cables from the Remote.

The 2 TRS jacks on the Remote 7 are hard wired to 2 of the 5 pin DINs, because we did not want active circuits on there. So when you use the DIN and TRS at the same time, the voltage will be lower, kind of like using a headphone splitter. So I wouldn't try pushing the length of the TRS cables from there.