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Teletype and ER-301 Basics


I don’t know if this is a huge faux pas:

Does anyone have the latest TT firmware beta in a built form? I’ve stumbled my way across various documents, trying to install the necessary libraries, but I seem to be stuck in avr32-toolchain :-/

Would love to try out the 301 integration. Thanks!


I just went through a similar exercise trying to find a hex file so that I didn’t have to compile it. I found one linked in the other 301/TT thread here on this site. I think this is the one I installed that shows 2.3 beta 3D2CCB9 when loaded:

No idea if this is most recent or not though. Maybe @scanner_darkly or @bpcmusic can advise us.


Okay, thank you! The installation instructions refer to a “update_firmware.command” file – can I just take this from any old firmware version?


I followed the instructions here:



you can follow the official instructions, just replace the hex file with the new one.

re: the latest beta - normally it will be in the official beta thread: https://llllllll.co/t/teletype-2-3-release-beta-2/11232

however, we had a recent scare where it appeared a teletype was damaged by directly plugging grid into it. teletype is not able to provide enough power to grids, grid must be powered externally. tehn was investigating and it looks like it was an unrelated issue, but until it’s officially confirmed my plan was to modify the firmware so that when a grid is connected it would ask a user to confirm it’s powered externally. i removed the posted beta until i can post a new version with the confirmation included (or until we know for sure there is no danger to teletype if you plug a grid directly by mistake). if you would like to try the firmware now just PM me and i’ll send you a donwload link.

3D2CCB9 is indeed the latest beta posted - i’m hoping to have a final beta posted in 2-3 weeks.


man I hate being the guy that asks this, but where or what cables would I need to buy in order to connect the teletype to the er-301?


I just bought some Dupont female to females from Amazon.



thank you @Joe

are the cables the only thing that is needed or do we have to also get the expander board that is on the lines forum? I was thinking of at least one ansible to expand the tt for other than er-301 purposes.


If you’ve had your 301 for a while you might need to mod the SOM board to make it work. If it’s newer, then your 301 is “Teletype ready”. Check here:


I think your Teletype should support two i2c connections without any more hardware. I have mine connected to the 301 and Ansible without additional hardware.


thanks again Joe. I got conflicting information from another source saying there is one connector on the TT and Ansible so a single cable needs to be split in order to add more (but that source and I may not be communicating clearly). Sadly I don’t have either units (waiting on the queue for the er-301 and waiting on delivery for the tt + ansible) to visually check. If I can connect an ansidble and er-301 to a single teletype with just the female to female cables then that would be great :smiley:



Well that’s good news then. If you have an ER-301 in Brian’s queue, then you shouldn’t have to mod it.

My Teletype is newer, and it has 6 total pins for ii. 2 sets of 3. Connections to the ER-301 and Ansible are working fine without additional hardware. Maybe there are differences in the Teletype hardware revisions too, where older versions only had 1 set of 3? Not sure - there are definitely people on this forum that know more about Teletype than me. Maybe they’ll chime in. :slight_smile:


As @Joe says, you only need 3 pins connecting a Teletype to another device.

Most of the compatible i2c devices have 6 pins (2 sets of 3). You can daisy chain signals using the other 3, unconnected, pins to send the Teletype signal on to another device.

I’ve had a 301, Just Friends and W/ connected at once with the bare-bones Teletype.


this is a picture of the TT unit i’m getting.

so looks like it would be good for an ansible and we-301?




ansible also has two sets of 3 pins so you’ll still have room to chain another i2c device down the line.


so can one TT control multiple ER-301s from the i2c? :scream:


I haven’t personally tried it but my understanding is that it can control 3!


…Ahh cool, I wondered what that extra set of pins was for! :grin:


As for the question of addressing multiple ER-301s: You definitely can. There are 100 ports for SC.CV and SC.TR available from Teletype per i2c slave address for the ER-301 and there are 3 such addresses. So if you want to address your first ER-301, you’d use a port between 1 and 100, while to address the second ER-301, you’d use a port between 101 and 200. You just have to configure the ER-301s to use different addresses for the i2c bus.


i’ve posted a preliminary documentation for the upcoming teletype 3.0 release here: https://llllllll.co/t/teletype-3-0-release-candidate-5-documentation-added/11232/291

among other things it includes a section on er-301 ops (done by @bpcmusic - thank you!)