Telex: Teletype expanders


Huge blunder in thinking on my part as to why was I thinking the TXo had any role.

What would the syntax be to divide the clock signal per output when using SC.TR as I’ve never defined the clock source?

Again regarding the SC.TR operator, how do I specify a specific input?


You’ll probably get better responses to SC specific questions over on the O|D thread.


You need an event to trigger that. I would put these scripts into M and create rules to trigger them (using the EVERY command, I believe). You can also put these into a numbered script, but that script needs to be triggered by a clock source.

Also, yeah it doesn’t sound like the Telex expander is what you want if you don’t want to physically patch into the ER-301.


I think I’ve just spotted my break in logic…because I have 100 possible triggers or cv’s to the ER-301 I was failing to associate a script number to an input number – oops.

What I was trying to do was along these lines:


SC.TR 2 : assign a different clock division

instead of:





It all seems so obvious now, but late at night when I first asked the question I should have tried sleep instead :slight_smile:

I also think I thought about addressing this in the Telex thread due to Brendon being key in this merger between Monome and O|D.


I would do the clock division within the ER-301 and use just one SC.TR from teletype. Seems easier to me and does not use another teletype script.


Maybe we create a thread here to talk about the i2c integration with the ER-301, link to the appropriate pages over at the OD site/forum, and have any ER-specific scripting discussions? If that sounds like a good idea, I can prime the thread in a little bit. :slight_smile:


Hi –

Longtime lines reader first time poster…

I’m planning on DIY-ing a TXi and TXo and was a little bit unsure about the exact header requirements for each -

If I have a few rows of 1x40 machined pin headers (male) and a few machined female for the teensies, a few rows of 1x40 standard 2.54mm (male + female - for connecting the boards), and a 2x40 standard 2.54mm (male - for power and maybe i2c), should I be good? I think I need to get something separate for the POGO 2x3 i2c connection but couldn’t figure out exactly where to get that or what pogo meant…

It wasn’t clear to me exactly what the device names on the BOMs were specifying…

Silly question but a little guidance would be appreciated!


Yeah, I did a crap job of labeling those things in the BOM. They just inherited their part names - but aren’t really tied to what you need to do. That is up to you. Just look at the number of pins, rows and gender.

I made the initial test TXo with standard headers all around. For the production run, I switched the board interconnects to precision headers (including the teensy one). This slimmed the module. You can also just solder the boards together and skip the female headers, but this makes makes it hard to troubleshoot.

If you need more help from here, I can go through and improve the list in the BOM. Might take me a couple days to get to it…

BTW: excited to see someone else building them!!!


Searched this topic for pcbs but not clear on status - kits/pcb/panels undecided atm, right? I’m getting some building supervision so diy looks really interesting here.


I’ve ordered more PCBs and panels for the TXo. I have a few half-built TXi in inventory.

At some point in the next month or two, I’m going to start building a handful of TXo and finish up the last of my TXi on hand. I’ll pop those on the site for sale when done.

At the same time, I’ll dedicate some PCBs and Panels for adventurous DIY folks.

All will go on sale at my store at the same time. I’ll notify in this thread when that happens.

All of the files are available on GitHub ( if you want to fab your own stuff and get started right away (without having to wait for my slow and busy rear-end). :slight_smile:


I’d love an improved BOM too if at all possible. I’ve a few builds under my belt now and feel that I could make a good job of building a couple. I’m still too green to understand the headers required but I’m sure I’ll find a way.


I’ll most likely get to a BOM update next weekend while I’m in the air for some travel. Thanks for being patient! :slight_smile:



hi @bpcmusic – i’m also DIYing a TXi and TXo. I’m thinking of just using front panel express. Just curious if you happened to have a FPD file for the front panels from prototyping stages etc? (currently attempting to convert ai/pdf -> hpgl(plt) -> FPE software = PITA :weary:)
No worries if you don’t, just thought i’d ask!


I haven’t used FPD in several years. I’ve not figured out a good workflow to deal with hpgl files. I thought that the new FPE software was better at this stuff. :frowning:


On another note, I pushed an update for the TXi and TXo BOM files that adds more clarification about the different types of headers and some links to other parts (including the LEDs which are important to match the specs if you want proper brightness and power consumption with the resistors in the circuit).

I didn’t link to specific pre-cut headers at Mouser as I find that just getting some cheap full-row headers and cutting them to suit is far less expensive. I also suck at finding them using Mouser’s search. Like, I just get totally lost in a sea of weird crap.


I did too! I’m sure i’ll figure it out, just thought i’d ask. Thanks for the updated BOM!


Hi @bpcmusic,

Maybe a quick question. The Telex GitHub page recommends the Teletype 2.0 beta but that appears to be updated 9 months ago. Is it compatible with 2.1 or 2.2?


Yes! I suggest making sure you are on the latest TT and TX versions. :slight_smile:


Yes. I would also suggest that! :smile:


Awesome. Thank you @bpcmusic and @laborcamp!


Lately I’ve been using Inkscape to export HPGL files that work fine with Front Panel Designer.