Coding

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John Hill
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Coding

#1 Post by John Hill » Thu Mar 31, 2022 5:26 am

PHXPhlyer wrote:
Thu Mar 31, 2022 2:32 am

Information exchange will be carried out via AFTN channel (for urgent short message) and postal mail.

Nice to know the olde AFTN is still chugging along! :-bd

(I used to write software for AFTN systems but Russia was not a client.)
Been in data comm since we formed the bits individually with a Morse key.

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TheGreenGoblin
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Coding

#2 Post by TheGreenGoblin » Thu Mar 31, 2022 6:39 am

John Hill wrote:
Thu Mar 31, 2022 5:26 am
PHXPhlyer wrote:
Thu Mar 31, 2022 2:32 am

Information exchange will be carried out via AFTN channel (for urgent short message) and postal mail.

Nice to know the olde AFTN is still chugging along! :-bd

(I used to write software for AFTN systems but Russia was not a client.)
APL or Fortran?

Ah I see it is an X.25 link meta-language, full of arcane ACKS and NACKS governed by the hierarchy of ICAO codes and location addresses.

It uses lots of Z's so Putin will be happy anyway...
ZCZC LAA005 12032000
DD OPKCZQZX
120900 OPSTZQZX

MESSAGE TEXT

NNNN
Though you remain
Convinced
"To be alive
You must have somewhere
To go
Your destination remains
Elusive."

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Coding

#3 Post by John Hill » Thu Mar 31, 2022 8:48 am

TheGreenGoblin wrote:
Thu Mar 31, 2022 6:39 am
John Hill wrote:
Thu Mar 31, 2022 5:26 am
PHXPhlyer wrote:
Thu Mar 31, 2022 2:32 am

Information exchange will be carried out via AFTN channel (for urgent short message) and postal mail.

Nice to know the olde AFTN is still chugging along! :-bd

(I used to write software for AFTN systems but Russia was not a client.)
APL or Fortran?

Ah I see it is an X.25 link meta-language, full of arcane ACKS and NACKS governed by the hierarchy of ICAO codes and location addresses.

It uses lots of Z's so Putin will be happy anyway...
ZCZC LAA005 12032000
DD OPKCZQZX
120900 OPSTZQZX

MESSAGE TEXT

NNNN

You would understand the need for the ZCZC if you were familiar with the Murray/Baudot code and how the telegraph machines of WWII era operated.
Incidentally, the Soviet delegates at the technical meetings in Montreal c. 1985, were at pains to ensure the end of line function included two carriage return signals which gave the mechanical printing mechanism time to return even at speeds as low as 5 characters per second.
Been in data comm since we formed the bits individually with a Morse key.

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Coding

#4 Post by TheGreenGoblin » Thu Mar 31, 2022 9:00 am

John Hill wrote:
Thu Mar 31, 2022 8:48 am


You would understand the need for the ZCZC if you were familiar with the Murray/Baudot code and how the telegraph machines of WWII era operated.
Incidentally, the Soviet delegates at the technical meetings in Montreal c. 1985, were at pains to ensure the end of line function included two carriage return signals which gave the mechanical printing mechanism time to return even at speeds as low as 5 characters per second.

I am aware of the Baudot-Murray code, but never used it per se. My early introduction to the RS-232C port and its heady max throughput 19.2 k baud, used ASCII control characters, still very much influenced by that code though (vide. Control + Z, and Control +C) ;)))
Though you remain
Convinced
"To be alive
You must have somewhere
To go
Your destination remains
Elusive."

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Re: Coding

#5 Post by TheGreenGoblin » Thu Mar 31, 2022 9:20 am

John I see that this Admin2 guy is more of Control + kind of guy. More EBCDIC then ASCII though! =))

I better watch myself lest I am terminated by that gentleman with the old (CTRL-D)- 0x05 EOF marker. :))
Though you remain
Convinced
"To be alive
You must have somewhere
To go
Your destination remains
Elusive."

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Re: Coding

#6 Post by John Hill » Thu Mar 31, 2022 9:26 am

Yeabut you are mixing the physical with the errr, etherial. RS-232c is a standard defining the signal levels on a cable whereas ASCII and Murray/Baudot defines character codes. I built many systems using Murray/Baudot on RS-232C connections.

Much of the international AFTN was still using Murray/Baudot codes and mechanical teletypewriters when IBM PCs became cheap and available. Integrating the PCs in to the AFTN network required considerable lateral thinking!
Been in data comm since we formed the bits individually with a Morse key.

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Re: Coding

#7 Post by John Hill » Thu Mar 31, 2022 9:31 am

TheGreenGoblin wrote:
Thu Mar 31, 2022 9:20 am
John I see that this Admin2 guy is more of Control + kind of guy. More EBCDIC then ASCII though! =))

I better watch myself lest I am terminated by that gentleman with the old (CTRL-D)- 0x05 EOF marker. :))
Ah yes, EBCDIC and the world of IBM which I was lucky enough to stay almost clear of except a somewhat brief encounter with 3270 protocols and machinery.
Been in data comm since we formed the bits individually with a Morse key.

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Re: Coding

#8 Post by TheGreenGoblin » Thu Mar 31, 2022 9:34 am

John Hill wrote:
Thu Mar 31, 2022 9:26 am
Yeabut you are mixing the physical with the errr, etherial. RS-232c is a standard defining the signal levels on a cable whereas ASCII and Murray/Baudot defines character codes. I built many systems using Murray/Baudot on RS-232C connections.

Much of the international AFTN was still using Murray/Baudot codes and mechanical teletypewriters when IBM PCs became cheap and available. Integrating the PCs in to the AFTN network required considerable lateral thinking!
I do understand that. I was just linking my experience of the hardware with the use of ASCII code. The Baudot character coding (5 bits) goes back to the 19th century.

Everybody is a pedant here today so I will point out that it is the Baudot-Murray code. Not the other way around... :p ;)))

We both know that the Baudot-Murray code was replaced by ASCII, I hope. :p

Wasting time here with you John is so much more fun than doing this (see below) which is work this morning...

Work.JPG
Though you remain
Convinced
"To be alive
You must have somewhere
To go
Your destination remains
Elusive."

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Re: Coding

#9 Post by TheGreenGoblin » Thu Mar 31, 2022 10:09 am

Though you remain
Convinced
"To be alive
You must have somewhere
To go
Your destination remains
Elusive."

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Re: Coding

#10 Post by John Hill » Thu Mar 31, 2022 6:45 pm

TheGreenGoblin wrote:
Thu Mar 31, 2022 10:09 am
For the inner nerd...
The challenge faced by telegraph engineers of the Baudot and Murray era was synchronisation between sending and receiving ends then around about 1926 some chap whose name I forget invented 'stop-start' signalling.

ITA2 has various versions including one for meteorological use which prints weather plotting symbols and no doubt there are versions for various character sets in use around the world. Then of course the five numeric groups in the grid wind temp messages can be automatically processed to produce a graphic of the data on a dot matrix printer but I doubt anyone still uses that.
Been in data comm since we formed the bits individually with a Morse key.

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Re: Coding

#11 Post by John Hill » Thu Mar 31, 2022 7:29 pm

While we are in pedant mode would you please contact Britannica and correct them..

https://www.britannica.com/topic/code-communications
"One such system was the Baudot code, which encoded complete phrases into single words (five-letter groups) for use by telegraphers."

I suspect they are referring to Bentley's code or something similar.
Been in data comm since we formed the bits individually with a Morse key.

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Re: Coding

#12 Post by John Hill » Thu Mar 31, 2022 8:58 pm

While we are on the subject of codes and the AFTN I should mention that Morse code was used on the AFTN in the Pacific area at least until 1975.
Been in data comm since we formed the bits individually with a Morse key.

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Re: Coding

#13 Post by TheGreenGoblin » Thu Mar 31, 2022 9:03 pm

John Hill wrote:
Thu Mar 31, 2022 7:29 pm
While we are in pedant mode would you please contact Britannica and correct them..

https://www.britannica.com/topic/code-communications
"One such system was the Baudot code, which encoded complete phrases into single words (five-letter groups) for use by telegraphers."

I suspect they are referring to Bentley's code or something similar.
John if we carry on like this we will end up discussing Martin Hollerith et al...

On the comms front I have just pulled out my dusty textbook on the mathematics of information and communication modelling ref. Shannon and Weaver... something to discuss over a beer in Auckland one day. ;)))
Though you remain
Convinced
"To be alive
You must have somewhere
To go
Your destination remains
Elusive."

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Re: Coding

#14 Post by John Hill » Thu Mar 31, 2022 9:17 pm

Somewhere in my storage area I have ( I hope ) a small metal box to accommodate a two cell cycle-light battery. It has a little light on top and two test leads. The front of the box bears a rather poor condition "Hollerith " transfer (decal).
Been in data comm since we formed the bits individually with a Morse key.

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Re: Coding

#15 Post by bob2s » Thu Mar 31, 2022 9:27 pm

Would you two please get a room. :))

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Re: Coding

#16 Post by John Hill » Thu Mar 31, 2022 9:30 pm

TheGreenGoblin wrote:
Thu Mar 31, 2022 9:03 pm
On the comms front I have just pulled out my dusty textbook on the mathematics of information and communication modelling ref. Shannon and Weaver... something to discuss over a beer in Auckland one day. ;)))
I am sorry but I will not be able to travel to Orkland but if ever we do meet I hope we will have time to discuss the work of Agner Erlang.
Been in data comm since we formed the bits individually with a Morse key.

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Re: Coding

#17 Post by John Hill » Thu Mar 31, 2022 9:30 pm

bob2s wrote:
Thu Mar 31, 2022 9:27 pm
Would you two please get a room. :))
We have one, did you not notice?
Been in data comm since we formed the bits individually with a Morse key.

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Re: Coding

#18 Post by TheGreenGoblin » Thu Mar 31, 2022 9:31 pm

bob2s wrote:
Thu Mar 31, 2022 9:27 pm
Would you two please get a room. :))
We only have enough money for an 8 bit room! ;))) =))
Though you remain
Convinced
"To be alive
You must have somewhere
To go
Your destination remains
Elusive."

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Re: Coding

#19 Post by John Hill » Thu Mar 31, 2022 11:21 pm

Meanwhile AFTN 1955........it is a lot to demand but maybe this will work.


https://fb.watch/c5Y3weVSYY/
Been in data comm since we formed the bits individually with a Morse key.

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Re: Coding

#20 Post by ricardian » Fri Apr 01, 2022 1:01 am

John Hill wrote:
Thu Mar 31, 2022 11:21 pm
Meanwhile AFTN 1955........it is a lot to demand but maybe this will work.
https://fb.watch/c5Y3weVSYY/
I was an RAF Boy Entrant u/t Telegraphist II at RAF Cosford 1959-61 and "man's service" 1961-73. We were taught to touch-type and to send/receive Morse code at 18 wpm. Equipment in use for non-Morse was 50 baud teleprinters and torn tape relay procedures. We had to memorise ITA2 (eg 12 = A or -, 15 = Z or +, 1235 = Q or 1, 1245 = FIGS, etc) and it was useful when I joined GCHQ as a Radio Officer after demob, reading UG8 undulator tapes (Morse and ITA2) was a new experience!
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