<div dir="ltr">The MIDI spec specifies a maximum cable length of 50ft. That is dependent on the cable capacitance, which is not mentioned in the spec.<div><br></div><div>I own a ProCo 150ft snake cable that I used for live music, between the stage and the FOH mixer. During a recording session, I ran the snake cable from the basement to the main floor. There were MIDI devices on both floors, and we wondered how well MIDI would work over that snake cable. I made adapters for both ends - MIDI worked flawlessly over 150ft of cable. Later I found a spec for that snake cable and found that the cable capacitance was very low.</div><div><br></div><div>MC</div></div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Fri, Jun 28, 2024 at 12:04 PM Florian Anwander <<a href="mailto:fanwander@mnet-online.de">fanwander@mnet-online.de</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-style:solid;border-left-color:rgb(204,204,204);padding-left:1ex"><u></u>
<div>
<div>Kay from LPZW did this already in 2017
in the Schleußig (<a href="https://leipzigwest.org/?page_id=173" target="_blank">https://leipzigwest.org/?page_id=173</a>) ... ;-)<br>
<br>
Am 28.06.24 um 11:50 schrieb René Schmitz:<br>
</div>
<blockquote type="cite">
<p><br>
</p>
<p>If you have the space and budget, use two optocouplers: one for
each direction, that allows you even to sense which direction it
is. </p>
<p>(So you can change the output too...)</p>
<p><br>
</p>
<p>Where do I collect my prize? :)</p>
<p><br>
</p>
<p>Best,</p>
<p> René</p>
<p><br>
</p>
<div>Am 28.06.2024 um 00:06 schrieb
Mattias Rickardsson:<br>
</div>
<blockquote type="cite">
<div dir="ltr">
<div dir="ltr">On Thu, 27 Jun 2024 at 20:55, Andrei
Kudryavtsev <<a href="mailto:andrei.kudryavtsev@gmail.com" target="_blank">andrei.kudryavtsev@gmail.com</a>>
wrote:<br>
</div>
<div class="gmail_quote">
<blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-style:solid;border-left-color:rgb(204,204,204);padding-left:1ex">
<div dir="ltr">Speaking of TRS mess, found this one in the
recent application list for MIDI innovations:
<div><a href="https://midi.org/innovation-award/psimidi" target="_blank">https://midi.org/innovation-award/psimidi</a></div>
</div>
</blockquote>
<div><br>
</div>
<div>Oops, that has been solved in commercial products for
over 5 years. </div>
<div>But without those extra diode voltage drops! </div>
<div><br>
</div>
<div>(Assuming 1.9 V drop for the optocoupler and 2 x 0.3 V
drop for the Schottkys, and the new 3.3 V (+/- 5 % on the
lower side) logic level, there's 0.635 V left for the 220
ohm resistor. The current is then only 2.9 mA, far below
the required 5 mA. Oops2!)</div>
<div><br>
</div>
<div>(It would need to have 127 ohms instead of 220. But
with 5 V (+/- 10 % on the higher side) logic level, and
1.9 + 0.3 + 0.3 V voltage drops, you get 3 V over the
resistor. 23.6 mA is above the specified Abs Max input
current of the 6N138 optocoupler suggested in the MIDI
spec, even if the 6N137 used here will survive. Oops3!)</div>
<div><br>
</div>
<div>I'm sure similar gender-agnostic TRS MIDI In jack
solutions must have been implemented by several
manufacturers by now? It was a bit weird to see different
brands using different polarities when TRS MIDI emerged,
and even more strange to see MMA omit a solution for it in
the new standard. :-) </div>
<div><br>
</div>
<div>Thanks for the reading tip, Andrei!</div>
<div><br>
</div>
<div>/mr</div>
<div><br>
</div>
<div>PS: I wrote "TS" in my first message, mistake - should
have been "TRS". Sorry.</div>
<blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-style:solid;border-left-color:rgb(204,204,204);padding-left:1ex">
</blockquote>
</div>
</div>
<br>
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