Telex: Teletype expanders

i did catch myself doing TO.PARAM and such occasionally but hasn’t been a major issue. i’m good with either option.

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I would personally vote for TO. TI.
as this seems less confusing for me, less cognitive load trying to understand what you are doing for which module, you know that from writing it, well with multiple modules you will need to remember more :slight_smile:


Turns out my TXo worked this entire time! I gotta thank Brendon for the helpful troubleshooting messages. If you’re just going by the printable command reference, it’s missing the key step that you have to set an output to a CV first before you start its oscillator.

I can’t wait to dive into this after my vacation.


Totally made my night!!! Hooray!!!

The markdown reference has explanations for the extended and experimental functionality that are worth reading. They interact with the base TT commands in interesting ways. Printable is just for an on-hand reference.

When I’m shipping things, I’ll do a few tutorials. :slight_smile:

I’ll do a proper progress update tomorrow - in the meantime check out my upgraded travel rig - now self-contained:

Congrats again, @trickyflemming!!!


Here is the update that I promised. Wrote it yesterday - forgot to post it. :expressionless:

I’ve updated the Crazy Verbose Status + Timeline with the latest details. In short:

We’re still on track for my planned schedule of doing the final pricing, funds collecting and shipping at the beginning of next month (April).

Might slip a few days if life gets in the way - but I’ve got a good clip going right now.

I was able to get a lot of the little parts needed for assembly (jumpers, headers, etc.) cut to size and ready while I was recuperating from a cold and jet lag (and penguin joy). This will have me more ready for the assembly phase. Plus - I’ve moved like lightning through the TXi SMD work.

75% of the boards are complete; the only board left is the bottom board for the TXo. This is the most complex board, with a good number of components on both sides (including the pesky DAC). I’m moving pretty quickly now - but this one is going to take the remainder of the week and weekend to finish.

On @sam’s suggestion, I made a modification to my plans for the i2c cables. Originally I was making a black mark on one of the wires to help orient the ground wire. As they are multicolor, sometimes this worked and sometimes it was invisible. @sam tried using a sticker on his - which looked great:

The problem is - the pesky things would come loose on their own. I’m going to use a paint pen to clearly mark one of the sides so we don’t get confused (especially when one of the devices is racked).

TELEX Microsite | Ordering Process Details | Crazy Verbose Status + Timeline
Open Source Repository | Printable Command Reference


for your consideration

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wonder about that actual amount of devices(i imagine different devices contribute differently too)…
would TT+2xTXO+TXI+JUSTFRIENDS+1-2(possible future devices for i2c) sound like over the limit?(if not, maybe what would be approximate latency from end-to-end thinking of “worst” devices in that chain ends?)

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latency isn’t the issue. it’s bus traffic. you can put a ton of devices on the line provided care is taken with cable lengths etc.

you of course can always have multiple i2c busses that are isolated.

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Milestone Update

All reflow work for the TELEX expander build is complete.

Lots still to do before shipping - but this is a significant point in production. All of the SMD components are affixed to the boards.

Whew; that was a lot of work.

Next, I’m going to take care of the last bit of prep work that I need to do prior to assembly. A little bit of business travel this week will slow me down - but I should be able to continue to maintain the beginning of next month shipping date.

Then, it is time to start putting these things together and testing them. I’ll keep updating as I progress through this process.

Thanks to everyone for their support and patience!

TELEX Microsite | Ordering Process Details
Crazy Verbose Status + Timeline | Printable Command Reference


Check out that pile of component-filled TELEX PCBs - weighing 5.73 lbs


So, I’m thinking about getting into eurorack, and I’ve put together something in modulargrid… :wink:


@GoneCaving - damn funny!! I burst out laughing on my plane. :wink:

So - if you’ve been following the other threads, you will most likely be aware that in order to reliably connect more than 3-4 devices to your Teletype, a mechanism is needed to provide more “pull-up” on the ii bus. This can be accomplished by modifying your Teletype or by using an external bus board that provides the additional needed pull-up. (You can also hack the firmware on one of the Teensy on your expanders, but this is not recommended as it may put too much strain on the devices on your bus.)

There are now two powered DIY bus board options for the Teletype ecosystem that @tehn has kindly designed for the ii expansionist. One is designed to sit in your case and one is designed to mount on the back of your Teletype. I’m calling them the iiBusboard and the iiBackpack to keep myself sane.



I’m assuming that many who have reserved the pending expanders might like one of these puppies. They are DIY and quite simple to build - only 3 SMD parts that should be trivial to affix even for novices. That said, I’m also assuming that there are plenty of folks on the list for whom DIY isn’t their thing.

So - we need to figure out how to get these out there. I’ve added a couple of columns to the list for these peripherals. PM me if you will need one and indicate your preference. I’ll share the numbers in a few days and then we can figure out how to get this taken care of without delaying the expanders. :slight_smile:


If I could “heart” this post again, I would.

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That’s fair amount of PCBs, my guess is that this whole project scale went up quite beyond the initial expectations :slight_smile:
Thanks for info on ii bus problems and possible solutions, keep up the good work!

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do u have grayscale panels for this plz???/

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Thank you for the plain English and extraordinarily thoughtful description. Now if someone would just define “pull up” :slight_smile:

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Whew, and here I was thinking it was something I was unfamiliar with.


Perhaps closer to the mark:

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I’d suggest moving the TXi’s to the top row so patch cables aren’t obstructing the knobs :wink: