[GreenKeys] In search of AP or UPI nameplate

Tue Jan 7 15:45:39 EST 2025

Interesting! Looking at
https://www.smecc.org/teletype-typeset/telety10.jpg ,  it appears that the
alphabetic characters are Baudot with the "0" bit being a space. I think a
hole in the image is mark. It looks like the row marked 5 is the most
significant Baudot bit and is transmitted last in Baudot. The row marked 1
is the Baudot lsb and is transmitted first.

However,
https://www.smecc.org/teletypes_in_typesetting.htm#:~:text=Accordingly%2C%20it%20made,characters%2C%20at%20least).
says the order is reversed.

Looking at the ASCII to Baudot code in my NYT feed
(https://w6iwi.org/rtty/audio/nyt/), we see below.

$AsciiToBaudotTable = array(
// Index is ASCII code (0..127). 5 LSB of data is Baudot code, transmitted
// LSB first. MSB is set if FIGS is required.
// See https://en.wikipedia.org/wiki/Baudot_code#ITA2 with lsb on right
  0x00,       // ASCII null. Send blank key
  0x00,       // ASCII SOH, send blank key
  0x00,       // ASCII STX, send blank key
  0x00,       // ASCII ETX, send blank key
  0x00,       // ASCII EOT
  0x00,       // ASCII ENQ. semd blank key
  0x00,       // ASCII ACK, send blank key
  0x85,       // ASCII Bell.FIGS S
  0x00,       // ASCII BS, send blank key
  0x00,       // ASCII HT, send blank key
  0x02,       // Line feed.
  0x00,       // ASCII VT, send blank key
  0x00,       // ASCII FF, send blank key
  0x08,       // Carriage return
  ...
  0x04,       // Space

As an example, CR is 0x08 or 0b01000 . The mark hole on the TTS tape is in
row 4. Since uarts (whether electronic or mechanical) transmit the lsb
first, the row transmit order for Baudot wioutl be 1,2,3,4,5. The question
is whether row 0 is transmitted first or last. If transmitted last
(transmitted as row 123450), the first 5 bits would be receivable as
Baudot. For alphabetic characters, row 0 is a space. If it were mark, a
model 15 would be able to print the transmitted lower case characters with
the mark "0" bit just extending the stop bit (starting early). The shift
in TTS code shifts to capital letters instead of to FIGS.

So, how many of you have model 20s? Or, better yet, TeleTypesetters with
Linotype? I COULD provide an audio feed of the NYT for TTS code if anyone
has a way to print it.

Finally, it is interesting as to how bits are numbered. Here, bits are
transmitted in numeric order (12345). When UARTs became available, they
transmitted the least significant bit first (as opposed to SPI which
transmits the most significant bit first). Looking at the front panel of a
PDP-8, we find bit 0 on the left (most significant bit). Moving to the
PDP-11, bit 0 is on the right (least significant bit). This, to me, was a
major advancement. Now the weight of each bit was 2 raised to the bit
number (right most bit had a weight of 2^0, the next to the left is 2^1.
This makes so much sense, I'm amazed we did not start that way. The PDP-11
also introduced memory mapped I/O, which I also think is very clever. A
CPU no longer needs separate input and output instructions (like in the
PDP-8). Intel kept the separate input and output instructions in the 8080,
but Motorola went with memory mapped I/O in the 6800. So... bit order has
an interesting history!

If I were to translate NYT to TTS coded AFSK, would anyone have a way to
test it?

Harold
https://w6iwi.org

On Tue, January 7, 2025 12:36 pm, W2HX wrote:
> I have a (two?) western union "black box" ticket tape machines (5A? can't
> recall). These use a very similar print mechanism to the model 20 and also
> uses 6 bit. Jack WA2HWJ (W7TTY?) got it working for me at one point, but I
> never did anything with it (them?)
>
>
> 73 Eugene W2HX
> My Youtube Channel: https://www.youtube.com/@w2hx/videos
>
>
> -----Original Message-----
> From: greenkeys-bounces at mailman.qth.net
> <greenkeys-bounces at mailman.qth.net> On Behalf Of Harold Hallikainen via
> GreenKeys
> Sent: Tuesday, January 7, 2025 12:17 PM
> To: greenkeys at mailman.qth.net
> Subject: Re: [GreenKeys] In search of AP or UPI nameplate
>
> Interesting! A model 20, which uses the 6 bit Teletypesetter code (
> https://en.wikipedia.org/wiki/Teletype_Corporation#:~:text=%5B31%5D-,Model%2020,-(1940)
> ).
>
> The 6 bit code is described at
> https://www.smecc.org/teletypes_in_typesetting.htm#:~:text=Here%20we%20see%20the%20Teletypesetter%20code%2C%20presented%20on%20a%20handy%20pocket%20%22ruler%22.%20This%20is%20a%206%2Dbit%20%22superset%22%20of%20the%205%2Dbit%20teletypewriter%20code.%20The%20added%20bit%20is%20designated%20%220%22%20to%20fit%20in%20with%20its%20placement%20across%20the%20six%2Dtrack%20perforated%20tape.
>
> It's interesting that this was used by a radio station. I thought most
> stations used model 15 with its 5 bit code. Are you sure it's a model 20?
>
> If it is indeed a 20, I could look at doing a 6 bit code version of
> https://w6iwi.org/rtty/audio/nyt/ .
>
> Harold
> https://w6iwi.org
>
>
> On Tue, January 7, 2025 9:42 am, Chuck Robertson wrote:
>> I'm the guy who bought the Orange County teletype below. It's a Model
>> 20 that came from a radio station in Southern California via a
>> broadcasting school.
>>
>> Unfortunately the seller says the Associated Press or United Press
>> International nameplate wasn't included when the broadcasting school
>> got it. Anyone happen to have one or know where I can get one?
>>
>> Thanks
>>
>> Chuck Robertson
>>
>> Newton Centre, Mass.
>>
>> hootsk at gmail.com
>>
>>> It's too bad they pried off the nameplate before trying to sell it.
>>
>> On 2025-01-04 19:53, MIKE MCAULEY wrote:
>>
>>>>* Just passing it along. No affiliation etc.
>> *>> >>* Mike
>> *>> >>*
>> https://orangecounty.craigslist.org/clt/d/huntington-beach-vintage-upi
>> -ap/7815074760.html
>> <https://orangecounty.craigslist.org/clt/d/huntington-beach-vintage-up
>> i-ap/7815074760.html>*
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>>
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>
>
> --
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>>>> Jordan Spencer Cunningham's GreenKeys Search Tool:
>>>> https://teletype.net/gksearch 2002-to-present greenkeys archive:
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>>>> 1998-to-2001 greenkeys archive:
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>
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