[GreenKeys] Can anyone identify this machine

Fri Mar 2 09:58:42 EST 2018

Eric

Unfortunately I dont.

I normally use an ST5 .

What sort of loop does it produce? Here its generally 20 Ma using 80 
volts, I believe you are on 60 ma. I have no idea as yet what the No 2A 
needs, it could be it came with standard American coils or maybe one of 
the GPO mods was for 20 ma.

I am currently looking at a HAL ST5000 which I have pulled out of my 
pile of demodulators which appears to do both high and low tones, but 
unfortunately produces a 60 ma loop. I am hoping to get around that by 
using the FSK output which is alleged to be RS232 levels, to drive the 
similar input to my ST5. But for some reason the FSK out doesnt seem to 
be working, I need to get it onto the bench. If I could get this to work 
it would mean I can copy the ITTY and AUTOSTART broadcasts too.

I suppose with suitable software I could also do it using your converter?

But I do quite like doing it the "old fashioned way" as far as possible!

Martin

On 02/03/2018 00:12, Eric wrote:

> If you happen to have one of my usb serial to current loop adapters, we can probably come up with a translation map that would work!
>
> On March 1, 2018 6:55:39 PM EST, Martin <strowger at aeolian-hall.myzen.co.uk> wrote:
>> As I became the lucky winner of this item, I can now shed light on the
>> answer to this question.
>>
>> It is indeed a GPO Teleprinter No 2A and built around 1925 according to
>>
>> the label. The condition is not at all bad really, apart from the
>> keytops which are not the end of the world. Its also missing a few
>> things like a switch and a bell end of tape alarm and the tape reel
>> cover, but otherwise looks like it will be a nice TLC project. I was
>> very pleased to get it as it must be a very rare machine to find and
>> cost very little, even including shipping from East Scotland, I wonder
>> how many survive? It was hard to find references to GPO machines of
>> this
>> age, but I was able to find a good chapter on it in Herberts
>> Telegraphy,
>> dated 1930. This fully explains the details of operation so faulting
>> and
>> maintenance should be no problem. It even came with a reel of narrow
>> paper tape to fit which is a bonus. This book covers all GPO
>> Teleprinters 1 to 5, and seems to be a unique reference. Does anyone
>> know if a GPO Teleprinter No 6 existed? I cannot recall.
>>
>> It is more precisely a Typebar Teletype and was developed from the
>> Typewheel Teletype manufactured by Morkrum Kleinschmidt, known by the
>> GPO as Teleprinter No 1A.  The double space bar was one of several
>> modifications the GPO requested to be compatible with earlier models.
>>
>> The code differs slightly from standard Baudot Telex code and this
>> seems
>> to be tied in with the double space bar feature.  The letters are all
>> standard but the figures case is different except the numbers. There
>> are
>> a number of characters of the form "1/" "3/" etc, and I cant think what
>>
>> they were used for. Important differences though are the Letters shift
>> which becomes "/", CR and LF which become "+" and "-" and space becomes
>>
>> Letters shift.
>>
>> As I interpret the description of operation, there is only one code
>> that
>> produces a non printing "no advance" of the tape, and that function
>> maybe available only from the keyboard. I dont know which key as the
>> markings are missing.
>>
>> So every character advances the tape, and that is why Letters and
>> Figures shifts can also be spaces, as these are the only other non
>> printing codes. Driving this machine from a Baudot coded machine is
>> going to require some careful thought! At the end of a line one will
>> get
>> a "+-" . Every Letters shift will produce a "/" but Letters will be
>> re-selected by every space! Figures will act normally.
>>
>> Fun times ahead.
>>
>> Martin
>>
>>
>> On 20/02/2018 09:16, John Nagle wrote:
>>
>>>> From: "Alf Fisher"<alffisher2 at gmail.com>
>>>> Subject: [GreenKeys] Can anyone identify this machine
>>>>
>>>> Please can anyone identify this machine.
>>>>
>>>> 73, Alf, G3WSD
>>>>
>> URL:<http://mailman.qth.net/pipermail/greenkeys/attachments/20180219/5f2a44d7/attachment-0001.jpg>
>>
>>> That's an unusual machine. It's basically a Teletype Model 14 tape
>>> printer.  I have several of those.  But for some reason, it was built
>>> as a modified machine to print on the tape usually used in
>>> reperforators.  It's not a reperforator; there's no punch
>>> mechanism.  Nor is it a reperforator from which the punch has
>>> been removed.  The tape feed mechanism and shift system are
>>> like a Model 14 (the tape position shifts), and the tape
>>> guides are similar to, but wider, than those for the standard
>>> 5/16" or 3/8" tape.
>>>
>>> Notice the two spacebars.  That's very unusual.
>>>
>>> It looks repairable.  Worth repairing as an exotic
>>> variant. What typebars does it have? Punctuation?
>>> Fractions?  Weather symbols?
>>>
>>>                  John Nagle
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