Thanks Nick!

So I tried it on a 33, aaand it didnt work. At all. Turns out the weak sauce solid state relay was only good for 150ma tops, and I slipped with the current and prob sent more than that. It probably should drive a polar relay. I found a not-so-solid state drop in replacement good for 500ma in my garage, and it works at 110 baud!

image0.jpeg

Yes this 33 is in rough shape but seems to work!

Jeff

On Jan 26, 2023, at 8:17 AM, Nick England <[email protected]> wrote:


Go to this document and search for “50 baud”.
https://www.navy-radio.com/tty/navelex-tty-1977.pdf

 There are a number of machines that came with 50 baud gears instead of 45 or 75. 
Like TT-332A compared to TT-332. I think you have the A model aboard USS New Jersey. 
Nick


On Wed, Jan 25, 2023 at 11:36 PM Jeff G <[email protected]> wrote:
So last update - I tried it with the Volpe board again using a 5v loop, and I now realize I can set the Volpe board for the matching baud rates, and lo and behold it worked fine. However, it did not work right at 110 baud. I think the Volpe board has some limitations on stop bits, etc and while they say it works with a 33, it didn't work with this thing at all at 110 baud.

I poked and prodded it a bit; the UART seems to be used for all 3 baud rates, and register settings do change when I change baud rates, including 5 bit mode. I think in this case the rom is literally being used as a rom and the UART is doing the communication work. Changing the baud rate does change the transmitter frequency going into the UART.

I was half tempted to play with clocks and what not but I have other projects to work on, so other than maybe trying it with a 33 before I return it, it'll prob go back on a shelf somewhere. I know I can reliably do the same functionality with an Arduino and a relay shield, so I'll stick to that for testing purposes.

For future reference, I was able to look up a TI TMS6011 which was a drop in replacement for the S1882 UART for pinouts and info.

So question - maybe for Nick - are there any known Teletypes that run at 50 baud in the Navy realm?


Jeff








On Wed, Jan 25, 2023 at 6:44 PM John W9DDD <[email protected]> wrote:
You'd need to figure out how to load a different divisor into the BRG register.  I haven't followed the details that closely, but one of the questions I had was does it need to be powered down after changing setting or did it turn out to have some sort of processor?  If it's getting  the setting out of a ROM, the 45.45 stuff might be able n it but not used.

John, W9DDD


On Jan 25, 2023, at 5:06 PM, W2HX <[email protected]> wrote:

Thinking about my suggestion, it would probably adversely affect the 110 baud rate which you may want to preserve. It might be possible to re-strap the uart for 45 baud if you are able to find any documentation on the chip.

 

 

73 Eugene W2HX
Subscribe to my Youtube Channel: https://www.youtube.com/@w2hx/videos

 

From: [email protected] <[email protected]> On Behalf Of W2HX
Sent: Wednesday, January 25, 2023 4:49 PM
To: Jeffrey Golas <[email protected]>
Cc: Greenkeys <[email protected]>
Subject: Re: [GreenKeys] Navy Teletype Message Generator

 

I bet you can change the crystal on that board and get 45 baud out of it.

 

 

73 Eugene W2HX
Subscribe to my Youtube Channel: https://www.youtube.com/@w2hx/videos

 

 

From: Jeffrey Golas <[email protected]>
Sent: Wednesday, January 25, 2023 1:38 PM
To: W2HX <[email protected]>
Cc: Daniel Jones <[email protected]>; Greenkeys <[email protected]>
Subject: Re: [GreenKeys] Navy Teletype Message Generator

 

Yeah I hooked it up to a 5v loop and logic analyzer last night, and sure enough 50 baud is EXACTLY 50 baud. It sends baudot for the first two and ASCII for 110 baud. Seems like it works!

 

Attaching pics for fun and profit.

 

Jeff KC3GJX

 

<image001.jpg><image002.jpg><image003.jpg>

 

 

 

On Jan 25, 2023, at 10:24 AM, W2HX <[email protected]> wrote:



Maybe try adjusting your range finder? Front panel says 50 baud not 45 baud?

 

Sent from Nine

 

From: Jeff G <[email protected]>
Sent: Tuesday, January 24, 2023 9:26 PM
To: Daniel Jones
Cc: [email protected]
Subject: Re: [GreenKeys] Navy Teletype Message Generator

 

Nothin wrong with spitballing - I'm going to take it back out to the garage and fiddle a bit. One thing I was trying was I had piped a signal gen through it and to a speaker, and had Fldigi listening via a webcam, but it couldn't decipher, even putting it mark only mode. I'm going to see if my logic analyzer can record serial data. I also have one of those old Robot RTTY keyboards, not sure if that had a loop jack on it but I may pulling that out and see.

 

Jeff

 

On Tue, Jan 24, 2023 at 8:51 PM Daniel Jones <[email protected]> wrote:

I probably should have thought about it a little more before I sent the last message.  It’s outputting a loop current it sounds like and not audio to be converted.  

 

Don’t mind me while I go to the back of the room. Hi hi. 

 

Daniel 

 

On Jan 24, 2023, at 17:37, Daniel Jones <[email protected]> wrote:

Could it be SITOR by chance?  

 

Daniel

 

On Jan 24, 2023, at 17:08, Jeff G <[email protected]> wrote:



Unfortunately the VOLPE board can't make heads or tails of it either, no matter what baud or mode I use. Either the baud rate is wrong or I dunno what. In 45 baud mode, it prints gibberish similar but not identical to what the machine prints. I may have to take it back out to the garage and fire up the logic analyzer lol. Then I can also check to see the ASCII/BAUDOT pin on the MM rom to see what mode its actually using.

 

Jeff

 

On Tue, Jan 24, 2023 at 4:56 PM <[email protected]> wrote:

5815 maps to Federal Supply Classification (FSC) 5815 = Teletype and Facsimile Equipment.

Google hasn't made any sense out of the other numbers yet.

Wayne

WB4OGM

-----Original Message-----
From: Jeffrey Golas <[email protected]>
To: Greenkeys <[email protected]>
Sent: Tue, Jan 24, 2023 7:40 am
Subject: [GreenKeys] Navy Teletype Message Generator

Thought you guys and gals might find this interesting...I volunteer on Battleship NJ and found this tucked away. Appears to be Navy-like but mentions "project" on it, serial #3 lol. Other than WMS on the board theres no manufacturer.

 

Its a RTTY/Teletype message generator that does the "quick brown fox" message. Whats really interesting is that all that is based on ONE chip whose sole purpose is exactly that. A MM5220DF. Other chips in that series have similar purposes, like ASCII-BAUDOT conversion.

 

Theres what looks like a white CPU, but Icant find any docs on it. It almost looks like something they had a surplus of, and with no rom, possibly wired it as a NOP (no-operation) so that it would just be an 8 bit counter. I think anyway.

 

It does seen to work after cleaning all the switches, I plan to test on the loop. All it does is keying via a solid state relay. I tried piping my signal gen through it but Fldigi couldnt decode.

 




Jeff KC3GJX

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>>> Jordan Spencer Cunningham's GreenKeys Search Tool: https://teletype.net/gksearch
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