Telex: Teletype expanders


Wait, so one could use 2x TXb to connect i2c modules between close proximity cases? For instance, enabling Teletype to communicate with just friends in another case?


Theoretically, yes. i2c is fussy and doesn’t like even medium runs. I have, however, used it to do exactly that with a very short stereo cable and only one bus board providing power.

@okyeron TT-BusBoard-Jr is so awesome. :slight_smile: :slight_smile: :slight_smile:


This is amazing. Could 3 TXb’s be chained (1x powered busboard replacement, 2x passive bridges)?


I’m guessing, but I’m guessing probably not. But maybe. It all depends.

i2c is fussy about cable lengths. It wasn’t designed to be as fault tolerant as something like USB. When the bus gets too long, things stop working reliably. There is no easy way to math it out that I’ve found given how wacky things get behind the panels with the busboards, individual modules, and interconnects.

What I know is that if I use a rather short stereo cable, I can connect two rows together using two TXb. I’ve also been able to connect a 16n via a short cable to that configuration and have it work. Your milage will vary based on the number of modules connected to the bus and the length of your cabling (and the resistance that your specific cabling introduces).

Anyone wanting to do a complex i2c arrangement should be prepared for some patient experimentation. The basic rule of thumb here is closer together is better - which means that less cabling is better.

I’ve personally managed some massive setups this way - like a Teletype connected to 8 TXi and 8 TXo.

Though, another thing that I do is implement a daisy-chain setup between modules as opposed to a star configuration. That is why the Telex have two sets of the i2c pins separated from each other on the back.

So you can use short interconnects like the little one on the left:

Standard i2c Cable

Sorry there isn’t a clearer answer.


No that’s helpful, thank you.


I Haven’t slept
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Hi !
I’m.sorry if some.ask it already, i’m curious to know if it would be possible to use the txi (one or more) directly with the ER301 ? As four knobs + 4 extra inputs for exemple…


If you mean on the Teletype, then yes you can have scripts which send the TXi inputs to the ER-301 over i2c.


Like @rikrak said but… Without a Teletype… Well I’m not a specialist but I’m sure it’s doable, not with the actual firmware but I’m pretty sure it’s technically possible.


yeah i think it’s possible to control er-301 directly from telexi. would require an easy firmware mod, and you would need an i2c backpack or txb (something to power i2c).

alternatively like with faderbank you could use teletype to poll telexi values and pass them to er-301.


I mean without the teletype… Just as a direct expander.


Yes, with a mod of the firmware and additional pull-up resistors on the bus, it would be possible and it’s a great idea. The TXi and TXo use a Teensy like a Faderbank, there’s no reason it wouldnt work imho


Even if you could, not sure there would be a huge advantage over just using some straight up analog offsets into the 301’s front panel inputs, other than reducing some cable clutter.

One of the big advantages of the TXi and Teletype is that you can do some transformations or decision making on the input values before sending them along to another device like the 301.


Maybe not - but the TXo might be a thing…:thinking:


Do you mean, as ER-301 expanders ?


Yes, I am dreaming of something to emit event related gate or trigger signals from the ER-301 since I have one. Like End of Slice or End of Cycle. It could trigger an event in the modular when a sample has been played to chose the next one for example. Or just to create some self generated music.


I have teletype, but sometime i would just need 4 knobs connected directly to the ER301, without teletype (to save space).


What he said. :slight_smile:

If you were intrepid, the 16n i2c section would be a great starting point (which was itself derived from the TXi). No promises, but when this sale is over, I probably could whip up a quick alternate version. :slight_smile:


“Well - everything is built, tested, accessorized, and boxed. I have some counting to do and some printing of extra manuals - but, the store will open soon. I’m planning 48 hours of notice. :)”

Announcement coming soon for the date and time for the store to open. I’m planning for the announcement on Saturday-ish … which will have the sale opening on Monday-ish.


Perfect timing! My TT arrives tomorrow. Any ideas on when you’ll start shipping out?