Telex: Teletype expanders


@bpcmusic rules, but we already knew that. :mage:

I failed to report back that I updated the rest of my TXis and they also work great.


Hi @bpcmusic
Im new round here and just came across your telex expanders. They seem great!
I don’t suppose they are available as DIY i.e. pcbs and panels?


Hi @gwpt! I’m currently stocking up to do another small run of fully built TELEX. For those interested, I also plan to put a PCB and Panel option on the site. No ETA as of yet - items are currently being fabricated.

If you are in a hurry - all of the files that I use to build the things are open source and up on the github site awaiting brave builders and/or fearless fabricators (


Do we need to be in contact with you to be on the waiting list or are you going to make them available on your store only like the last batch?


I will announce here like last time with a drop date/time for the items on the store.

I advise not to get too anxious as completion will still be a few months out. I have a few other projects in the queue ahead of going into TELEX production mode. Also, the panels are still in fabrication.



I am not sure where things stand with firmware on both Telex units…
I have two from original run, and two from last run.
Do I need to perform any firmware updates?
If so, can you link here again instructions on how to do it?
Thank you!


Firmware is here:

And instructions are on this page:


Great! Thanks @bpcmusic Really looking forward to these! :slight_smile:


Really excited as well! Got a pair on the first run and am looking forward to working with more.


That would be really cool if there could be a waiting list for those who missed out on the last run honestly.


I do hope you get a couple of Telex this go round @madeinspace and would hope that @bpcmusic put you on a priority as you were so close last time. I bought two TXo’s and one TXi that day and now with the i2c connection to my ER-301 I feel well setup with my Monome system so far. Now I need a Grid and I’m certain I’ll be wanting the New Thing! whatever it may be…oh and the Faderbank :slight_smile:


Thanks yeah really hope I can make it this time. Is there a new monome thing coming up? :smiley:


Watching closely time to get into this


noticed this morning that the envelopes coming out of my TXo seem to dip below 0v at the end of decay. i was using it with a filter and could hear it happening so i ran i through the scope on er-301 to see what was going on and sure enough, there is a brief dip. i have attack set to zero, the decay set to 1000 and the voltage is controlled by a TXi knob. Is there something really obvious that would cause this? i don’t use TXo for envelopes very often so i might’ve missed something…


Thanks for reporting. Can we get a little more info?

  • What is your resting voltage at TO.CV 1 0? Have you calibrated it?
  • What do you have your envelope’s peak voltage set to?
  • What firmware version are you running on the TXo?
  • How far below zero are you seeing the dip?

That will help us replicate/evaluate what you are seeing.

I’m excited to understand and (potentially) catch a bug! :slight_smile:

Is that weird?


Haha, not weird, means your a real dev :wink:


Up until now I’ve been using TT input 1 for clock duties regarding Telex TXo trigger duties. Tonight I was trying to find how I could use input 2 or 3 or 4 etc., to drive TR 2, 3, or 4 independently of the clock in TT input 1?


What exactly are you trying to do? The question isn’t totally clear. Thx!


I have a clock signal going into jack #1 on the Teletype.

The TXo SC.TR #1 is sending out a trigger to the ER-301 using the clock signal from the Teletype.

I want to use a clock division on SC.TR #2 for a trigger to another unit on the ER-301, so my idea was to patch another clock signal in jack #2 on the Teletype. As I’m typing this out I’m starting to feel that I’m missing something regarding using a math operator on the SC.TR command line???


Are you using the Teletype SC ops to directly control the 301? If so, that doesn’t involve the TXo at all.

I’m also still having trouble following what you’re trying to achieve. Could you share your TT code?

If you want a division of the clock coming in from Input 1 then you should be able to do that in the script, and then send the new divided clock to any output you like.

If you want a completely separate clock then you could use a separate input, in your script you would read from the new input instead of Input 1 to get the new clock…

I feel like I’m still not really understanding